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How to enter your firm's Companies House Presenter ID and Presenter Authentication in Tax Optimiser, and how to apply for them if you don't have them yet.

Explain a corrected prior period error or a change of accounting policy, and the amounts restated.

Send a period's accounts and Company Tax Return to your client from the period Overview. They read, sign and approve online, or ask a question, and cannot open or change anything else.

Show the historical cost comparison and the revaluation reserve movement for fixed assets carried at a valuation.

Your accountant has sent you accounts or a tax return to approve. Sign in, read each document, then sign and approve, or send a question back.

Disclose listed shares and other financial assets carried at fair value, the gain or loss for the year and how they were valued.

Prepare a charity's accounts in charity format: a Statement of Financial Activities by fund, a trustees' annual report and an independent examiner's report under the Charities SORP, or receipts and payments accounts for a small charity that is not a company. In beta.

A step-by-step guide to the Imported Data tab: matching each imported account to a common account by hand or with AI suggestions, and checking the result.

Mark a company's accounts as audited or as an audit exempt subsidiary (s479A): the auditor's details, the four opinion types, and what changes in the accounts and the iXBRL. In beta for accountant firms.

Worked trial balances for a dormant company: never traded, used to trade, subsidiary, investment holder, director's loan and Companies House fees.

Write the strategic report that medium and large companies must include, and small companies may: the sections, the templates, moving directors' report matters, approval and the checks. In beta for accountant firms.

Prepare a small company's accounts under full FRS 102: a statement of changes in equity and a cash flow statement, plus staff costs, directors' remuneration, tax reconciliation, reserves and financial instruments notes. In beta for accountant firms.

A property company files accounts at Companies House and a CT600 with HMRC every year. Here is what changes for a landlord company and where to start.

Investment property at fair value, the revaluation, deferred tax, the mortgage and the notes a property company needs under FRS 102 Section 1A.

Type the rents and letting costs as UK property, move the mortgage interest to Non Trade Debit, and leave the revaluation out: a worked example to GBP 2,850.

File a property company's accounts at Companies House and its CT600 at HMRC from one wizard, and what to check first.

Every Community Interest Company must send a CIC34 report to Companies House with its accounts each year. What goes in it, when it is due, the fee, and how to file it online or by post.

What every box on the CT600 Company Tax Return means, how Tax Optimiser fills it, and where the figure comes from - with an entry for each box on the 2026 form.

What a Companies House presenter ID is, how to apply for one on GOV.UK, and where to enter it so you can file your own company's accounts.

What counts as dormant for Companies House, what dormant accounts contain, and how to file them with the Dormant Accounts Wizard.

When your accounts are due at Companies House, how the accounting reference date sets the deadline, and what happens when you change it.

How statutory accounts for a limited liability partnership differ from company accounts in Tax Optimiser: members and designated members, no directors' report or tax line, members' interests on the balance sheet, the reconciliation of members' interests, and one credit covering the accounts and the SA800.

How FRS 105 (micro-entity) and FRS 102 Section 1A (small company) accounts differ, and the size thresholds - including the higher limits from 6 April 2025 - that decide which one your company uses.

What Making Tax Digital for Income Tax is, the four-step setup on your dashboard, and the difference between demo mode and live mode.

Show long-term creditors from your trial balance, the amount due after five years and any security given.

Enable the service, link Companies House, add your UTR and create your first accounting period.

Disclose capital expenditure the company has contracted for at the year end but not yet recorded.

Switch on the VAT service, enter your VAT registration number and find your way around.

Find your way around the View Accounts screen: the live preview, page links and the editing actions.

Two versions of one set of accounts: what filleting removes, where each version is filed, and how amended filings work.

The automatic penalty for filing accounts late: the bands, the doubling rule, extensions and appeals.

The R&D supplementary page of the Company Tax Return: who has to file one, how the seven RDEC steps turn a claim into cash, and what every box from L5 to L210 means.

Already filed your accounts at Companies House? How to file just the CT600, why HMRC needs the full accounts, and how to check they match the filing.

Bring a year's figures in from Xero, Sage 50 or any spreadsheet, map them to HMRC and Companies House-ready accounts with AI help, and make it balance.

A members' club or association files a CT600 but nothing at Companies House, and its members' income is not taxable. Here is the whole journey, from signing up to sending the return.

Import from Xero, QuickBooks or a spreadsheet, or key the trial balance by hand - then make sure it balances.

Follow a trading loss from the year it is made to the year it is used: boxes 780, 160 and 285, losses before and after April 2017, and pulling the balance into the next period.

When a company's accounts cover more than 12 months, Tax Optimiser keeps one set of statutory accounts but splits the Corporation Tax into two CT600 returns - the first 12 months and the remainder. How the split is decided, how profits, capital allowances and losses are divided, and how both returns are filed.

Four ways to get a year's figures into Tax Optimiser, how to choose, and a walkthrough of Simple Entry: numbered boxes for micro-entity accounts and Corporation Tax, from first figure to filing.

Renew your HMRC connection in two minutes, and sort out the "incorrect Government Gateway account" message.

Read the loss movement, record brought-forward and carried-back losses (pre- and post-2017), and let the carried-forward balance calculate itself.

Sign the accounts, clear the pre-flight checks, and file to HMRC and Companies House through the guided wizards.

Clear the validation list, record who signed and when, and keep the signed copy on file - then you are ready to submit.

Work through the calculation sections - disallowables, adjustments, donations and non-trade income - and watch the payable figure update live.

The 45% charge on restitution interest paid by HMRC - when the CT600K is needed, how to complete it in Tax Optimiser and what every box from K1 to K35 means.

Set the organisation's Corporation Tax company type to Charity or CASC and the CT600E supplementary page appears, ready to complete and file with the CT600. A company only owned by a charity has its own company type and files no CT600E.

The controlled foreign company charge, the foreign branch exemption election and hybrid mismatch disclosures - how to complete the CT600B in Tax Optimiser and what every box from B1 to B85 means.

A company that has never traded but has a notice to file from HMRC files a nil CT600. How to mark the period dormant, check the nil computation and send the return with dormant accounts attached.

Every set of accounts and every CT600 hangs off an accounting period. Here is how the system creates them for you automatically from Companies House, and how to add one by hand when you need to.

Replace a set of accounts you've already filed: check the original went through, correct the figures, mark them as amended, fill in the revision detail Companies House requires, and re-file.

Which dealings with directors, their families and their other companies need disclosing in small company accounts, and the templates that help you word it.

Disclose commitments and security not shown on the balance sheet that are not covered by the capital, lease or pension commitment notes.

Disallow depreciation, record your asset additions, and claim the Annual Investment Allowance.

A Community Interest Company files the same CT600 and accounts as any company. The difference is the CIC34 report it sends to Companies House each year - here is how to prepare it in Tax Optimiser.

Accept the declaration, get HMRC's acceptance back and keep the receipt as proof of filing.

Looking for a CT600 or a set of accounts you have already filed? Where to find it in Tax Optimiser, how to read the status and how to download a copy.

The Economic Crime and Corporate Transparency Act changes to accounts filing, now due on 1 April 2028, and what to check before then.

AVEC, VGEC and the creative reliefs - how an expenditure credit becomes a payable credit, how to claim it in Tax Optimiser and what every box on the CT600P means.

How a company with investment business deducts its management expenses and the capital allowances on its investment-business assets - the Management Expenses tab, excess carried forward, and CT600 boxes 245, 255, 850 and 733.

The cross-border royalties supplementary page - when the CT600H is needed, how to complete it in Tax Optimiser and what every box from H1 to H5H means.

Need fuller accounts than FRS 105 allows? Switch the period's Accounts Type to FRS 102 Section 1A from the Overview and keep your trial balance, journals and tax computation.

Three Firm Settings switches add SA100 Returns, SA800 Returns and MTD ITSA to the firm menu, each a firm-wide list of clients for a tax year with status, search and a link into the return.

One card per partnership on the short or full statement: the mandatory UTR, name and join/leave answers, the profit chain HMRC actually taxes, Class 4 and voluntary Class 2, and the full statement's income shares.

The Return Preview section draws the whole return on HMRC's SA100, supplementary and SA110 forms, with every box clickable through to where it is entered; the same document downloads as the full SA100 return PDF.

Drag your spreadsheet onto the open period and check the nine boxes it fills.

Track what HMRC says you owe and have paid, and settle into the quarterly routine.

The four FRS 105 notes explained, including the mandatory average-employees figure and how wording templates work.

Say who controls the company — an individual, a parent company or nobody — using one of three templates.

How Tax Optimiser builds the directors' loans table from your loans to participators, and what to add when a loan is interest-bearing, repaid or written off.

How the average number of employees is disclosed in FRS 105 and FRS 102 Section 1A accounts, and where Tax Optimiser gets the figure.

How to disclose loans to directors and guarantees given on their behalf in micro-entity accounts.

The fair value reconciliation for property held to earn rent or for capital growth, with the basis of valuation.

Read the cross-referenced computation, finish the statutory accounts, and clear the validation checks.

Reporting a DOTAS Scheme Reference Number on the Company Tax Return - when the CT600J is needed, how to complete it in Tax Optimiser and what every box from J1 to J50A means.

The tonnage tax supplementary page - when the CT600F is needed, how the profit for each ship is worked out, how to complete it in Tax Optimiser and what each box from F1 to F70 means.

How a company is taxed on the sale of property, shares and other capital assets - recording disposals on the Chargeable Gains tab, using capital losses, and what goes in CT600 boxes 210, 215, 220 and 825.

Claiming and surrendering losses between group and consortium companies - how to complete the CT600C in Tax Optimiser and what every box from C1 to C225 means.

When no CT600 is needed, when a nil return is, and how to handle a company that was dormant for only part of the year.

Every individual client for one tax year with the state of their SA100: Not started, In progress, Waiting for HMRC, Rejected or Filed, the tax due and a Late marker after 31 January.

Every partnership and LLP client for one tax year with its SA800 status, from one screen, without selecting each organisation first.

One card per employment: the PAYE reference and director answer HMRC insists on, the close-company boxes, negative tax, information-only boxes, the box 18 cap, and how Class 1 earnings cap Class 4 National Insurance.

Short versus full pages, the £90,000 turnover limit, start and cease dates, the trading allowance in place of expenses, the profit chain and loss sign, Class 4 and voluntary Class 2, and how transition profits are taxed.

The SA106 page: income rows with their A to F columns, Foreign Tax Credit Relief from the HS263 sheet, overseas property and its chain to box 30F, foreign gains and life policies, the remittance basis, FIG claims, and the one-row-per-group limit.

Trust and estate income entered net from the R185 and grossed up automatically; the two non-repayable credits and how HMRC caps them; box 15 as tax paid; box 24 as a deduction.

The SA109 page: non-residence and the Personal Allowance, the non-repayable dividend credit, FIG regime claims and what they cost, Overseas Workday Relief, the 12% Temporary Repatriation Facility charge, remittances and DTA relief.

How a firm sends the finished SA100 to the client to read, approve and sign electronically: the firm setting, the Send for review form, what the client sees and can do, statuses, resending and withdrawing.

The firm-wide view of Self Assessment: the Individuals list's SA100 year, status and tax due columns, the dashboard card, and starting the next tax year with or without copying from the last.

Where the Partnership return (SA800) menu appears, what the returns list shows, what New Partnership Period prefills for you, and what a return costs to file.

A breakdown of the balance sheet debtors figure into trade debtors, group and related amounts, prepayments and other debtors.

How a company carries a trading loss back against earlier profits - the 12-month carry-back, three-year terminal loss relief when the trade stops, the Carry back to earlier periods panel, amending earlier returns, and CT600 boxes 45, 275, 280 and 780.

The 4% tax on residential property development profits above a £25 million group allowance - when the CT600N is needed, how to complete it in Tax Optimiser and what every box from N1 to N285 means.

The Freeports and Investment Zones supplementary page - when the CT600M is needed, the two enhanced allowances, how to complete it in Tax Optimiser and what each box from M1 to M30 means.

The ring fence trades supplementary page - when the CT600I is needed, how ring fence profits and the supplementary charge are taxed, how to complete it in Tax Optimiser and what each box from I1 to I160 means.

The insurance supplementary page - when the CT600D is needed, how to complete it in Tax Optimiser and what each box from D1 to D5 means.

QuickBooks connection lapsed? Reconnect in a couple of minutes from the Trial Balance or the Organisation page, then sync again. Nothing you have done is lost.

Every Making Tax Digital client for one tax year: HMRC connection, quarterly updates sent, overdue updates and the final declaration, from the obligations already fetched.

The SA105 page: property count and about-the-business ticks, Rent a Room, the £1,000 property allowance in place of expenses, the cash basis, residential finance costs and their 20% reduction, and the profit chain HMRC actually taxes.

Gains by asset category with the counts HMRC requires; losses and the £3,000 exempt amount in HMRC's order; 18%/24% and BADR rates; tax already paid; non-resident CGT; and the computation summary or PDF HMRC insists on.

The SA101 page: other income and the box 14/15 pair, life-insurance gains with top-slicing relief, share schemes and lump sums, EIS/SEIS/VCT reliefs, the Married Couple's Allowance groups, pension savings charges and the formats HMRC checks.

Tell Tax Optimiser which sheet and cells of your spreadsheet hold the nine VAT-return boxes.

The Company Information, Dates, Pages and Addresses windows - the descriptive details that appear throughout the document.

Manage the directors list, sync it from Companies House, and designate who signs the balance sheet.

The movement in long-term investments such as shares in a subsidiary, taken from your trial balance, plus the details small companies give about subsidiaries.

Break down the creditors due within one year on the balance sheet, line by line from your trial balance.

The once-a-year declaration that crystallises your tax bill, what must be done first, and how to re-open a year to amend it.

How a company gets credit for foreign tax on its overseas income - adding sources on the Double Taxation Relief tab, how the credit is limited to the UK tax on each source, and what goes in CT600 boxes 450, 470 and 475.

Which capital allowance goes in which CT600 box: AIA, full expensing, the main and special rate pools, structures and buildings, and the expenditure boxes 760 to 775.

A CIO files a CT600 but nothing at Companies House, and its SORP accounts go to HMRC as a PDF. Here is the whole journey, from signing up to sending the return.

The Gateway login is firm-wide with a per-client override; the Presenter ID is firm-only for firm-managed clients. Here are the rules, the override, and the errors.

The yearly duties of a dormant company at Companies House and HMRC, and which ones Tax Optimiser files.

A VAT return can't be changed once HMRC has accepted it. Correct the error on your next return, or report it to HMRC, depending on its size.

Practise the HMRC connection in demo mode, then grant authority for real and let your periods flow in.

Analyse the deferred tax provision or asset into revaluations, tax losses and other timing differences.

An optional text note describing what the company's turnover is made up of.

How a company gets money back from its Company Tax Return - R&D and creative credits paid in cash, Income Tax repaid, bank details - and what every CT600 repayment box from 860 to 970 means.

How the 19% and 25% rates, marginal relief and associated companies work, with three worked examples and every CT600 box from 326 to 440.

How to correct a Company Tax Return that HMRC has already accepted: the two-year limit, Submit as amended, returns first filed elsewhere, and what to do when the window has closed.

Mark rental income and letting costs as UK property in the P & L, and Tax Optimiser reports the property business in boxes 190, 805 and 250 - separately from the trade.

From the balance sheet to Send Accounts: every screen for a company that was dormant all year.

When Corporation Tax is due, where to find the amount and date in Tax Optimiser, quarterly instalments for large companies, and how to record what has been paid.

Xero connection lapsed? Check the Xero card, reconnect in a couple of minutes, then sync again. Nothing you have done is lost. You can also disconnect Xero from the same card.

Paid the submission fee against the wrong year? Move the payment to another accounting period of the same company from the Billing page, as long as nothing has been submitted for it.

Stuck on something? Raise a support case from inside Tax Optimiser. Attach screenshots, get an email when the support team replies and keep the whole conversation in one place.

How the note set grows under FRS 102 Section 1A, which notes fill themselves from the trial balance, and the accounting policies window.

Land & Property, Foreign, Chargeable Assets and Savings on one screen - each page files only when it carries figures, and the totals calculate themselves.

Show the movement on a capital contribution reserve: opening balance, contributions received and amounts utilised.

What the notes to your statutory accounts are, how the Notes screen in Tax Optimiser works, and a guide to every note.

How to choose, word and print the accounting policies note, with a guide to every policy in Tax Optimiser.

How to authorise Tax Optimiser to talk to HMRC, the difference between an individual and an agent connection, and when to reconnect.

Filing a client's accounts as a firm: credits instead of per-period fees, the firm's presenter credentials, and the pre-flight checks before the wizard sends.

Where annual payments, non-exempt dividends from overseas companies and income received net of Income Tax go on the CT600 - boxes 175, 180 and 185 in Tax Optimiser, with a worked example.

The live SA302-style calculation: the staged statement with its non-repayable credits, CGT, pension and TRF charges, the band breakdown, PAYE coding adjustments, the carried-forward table, amber and red warnings with Go to links, and the SA302 PDF.

Depreciation in the accounts is not deductible for Corporation Tax. How to add it back in Tax Optimiser, record your fixed assets so capital allowances replace it, and reverse profits or losses on disposal.

Interest on borrowing that is not for the trade - shares, let property, investments - is a non-trading loan relationship debit. How to move it out of the trade with the Non Trade Debit grid, and how a non-trading deficit is relieved in boxes 795, 260 and 263.

The 100% first-year allowance for new electric vans and other zero-emission goods vehicles - who could claim it, its end for companies on 31 March 2025, how to record the vehicle in Tax Optimiser, and what goes in CT600 boxes 723, 748 and 760.

Tell Tax Optimiser which sheet and cells of the client's spreadsheet hold the nine VAT-return boxes.

Give a client a login to their own organisation - they only ever see the organisations they belong to.

Prepare and file the 2025-26 SA800 Partnership Tax Return for LLPs and partnerships: a six-step wizard, self-calculating boxes, the official form as a PDF, and direct HMRC filing. In open beta for accountant firms and partnerships alike.

State that the company has no share capital and how much each member guarantees on a winding up.

Show the future minimum payments under non-cancellable operating leases, analysed by when they fall due.

When the company guarantees a director's personal borrowing, s413 requires it to be disclosed. Here is how to complete the table and the description.

How the stock figure on your balance sheet is split into raw materials, work in progress and finished goods, straight from the trial balance.

How to disclose capital commitments, other financial commitments and contingent liabilities in micro-entity accounts.

The opening note that identifies the company: its name, legal form, where it is registered, its number and its registered office.

A breakdown of the tax charge into corporation tax and deferred tax, read from the trial balance.

The cost, depreciation and net book value table for property, plant, vehicles and equipment, built from the trial balance.

A text note stating the dividends paid or proposed in the year, with templates for the usual wording.

A one-sentence statement that the accounts follow FRS 102 Section 1A, which Tax Optimiser fills in for you.

The six-character code Companies House needs to accept your filing: where it comes from and where it goes in Tax Optimiser.

How non-trading gains and losses on intangible fixed assets and capital allowances against non-trade income reach the CT600 - boxes 195, 265, 290 and 830 on the Intangibles & Other Reliefs section.

Declaring the CT600 on a different day from the accounts approval? How to put the right date in box 980 without changing the approval date in the accounts.

The mechanics every return page shares — HMRC box badges, groups, hints, the boxes HMRC insists on, inline warnings and self-adding totals — then the SA100's own income sections for interest, dividends, pensions and other income.

Where each supplementary page is covered, the two things not yet covered, and how HMRC's own validation rules run before a return is sent.

Add a client organisation from your Organisations list - only the VAT registration number is required.

Practise the HMRC connection in demo mode, then go live with your firm's agent account and let the client's periods flow in.

Upload the client's spreadsheet, check the nine boxes, accept the declaration and keep HMRC's receipt.

Add colleagues to your firm so they can act for your clients with their own login.

The full SA800 income and expenses page, or the three-line boxes 3.24 to 3.26 below £90,000: entering income and expense totals, the capital allowance pools, an optional breakdown of disallowables, and how the calculated boxes 3.65 and 3.73 drive the rest of the return.

Adding partners, boxes 6-12, entering each partner's share, and the live checks: the allocation-vs-return warning and the UTR check that prevents error 8205.

Every set of accounts and every CT600 hangs off an accounting period. Here is how the system creates them for you automatically from Companies House, and how to add one by hand when you need to.

Disclose possible liabilities, such as guarantees given or legal claims, that are not provided for in the accounts.

Disclose significant things that happened after the year end but before the accounts were approved, such as a dividend declared after the year end.

How to add a note with your own heading and wording to FRS 105 or FRS 102 Section 1A accounts.

The cost, amortisation and net book value table for goodwill and other intangible assets, built from the trial balance.

Where your personal details go, and why your National Insurance Number is required before any submission.

How Tax Optimiser retrieves your income sources from HMRC, the three business types, and what each business holds.

Who can skip an audit, when shareholders can insist on one, and the statement the directors must sign.

Directors' loans, the section 455 charge (35.75% from April 2026) and the relief that cancels it - how to enter loans in Tax Optimiser and what every box on the CT600A means.

The VAT and MTD subscription: the free period, adding or changing a card, finding invoices, changing the billing contact and cancelling.

The one-off fee a company pays to file a period: how much, when you are asked, how to pay and where to find the receipt.

Every period follows the same three stages before you can file: get the trial balance in, build and review the accounts, and build the Corporation Tax computation. Here's the map.

What the Self Assessment (beta) feature does, how it differs from MTD ITSA, every SA100 page it supports, the return preview and client sign-off, and the two things it does not yet cover.

Enter a year-end adjustment as debits and credits, approve it, and see exactly what it changed.

Use the Trial Balance tab of a working paper to compare each balance with last year, tick it as confirmed, explain it in a note and attach the evidence.

Leave a review point against any balance, see at a glance what is still outstanding, and clear each one with a response.

What belongs in CT600 box 205, how the Non Trade Income grid takes the income out of the trading profit and taxes it on its own line, and what each column does.

Disclose the fair value of forward contracts, swaps and other derivatives, and describe what they are for.

Explain a final salary scheme and show the assets, obligations and movement behind the pension balance.

The checks that block a return HMRC would reject (each linked to its step), the page 8 declaration, the review summary, the View form window with its clickable boxes, printing the official SA800 form and its schedule, what Submit really does, and what happens afterwards.

State the number, class and nominal value of the company's allotted shares, agreed to the trial balance.

Describe the company's pension arrangements, the cost for the year and any contributions outstanding.

Disclose material arrangements that are not on the balance sheet but expose the company to risks or benefits.

Show the movement on provisions other than deferred tax, from opening to closing balance.

Analyse the current asset investments on your balance sheet between listed and unlisted holdings.

A table of the items charged or credited in arriving at operating profit, read from the trial balance.

The per-business settings that shape how figures are reported: cash or accruals accounting, standard or calendar quarters, and full or consolidated expenses.

Asking HMRC to work out the tax on what you have reported, the three kinds of calculation, and how to read the result.

What companies and accountant firms pay for in Tax Optimiser: per-period fees or credits for year-end filing, and a subscription for VAT and MTD.

How to add a second company to the Tax Optimiser login you already have, finish its details, and switch between your organisations.

The map of the journey: set your firm's filing credentials once, then create each client and file accounts and Corporation Tax through the two wizards.

Where the firm's Presenter ID and Government Gateway login live, what each one is, and how to obtain a Presenter ID.

Four ways to add a client: the Companies House lookup, by name, from QuickBooks or Xero, or the full details form. Then what to complete before you file.

Filing the CT600 for a client: the UTR and Gateway login it needs, what the warnings mean, and the final confirmations before sending.

Pension contributions, Gift Aid, Marriage Allowance, the High Income Child Benefit Charge, Blind Person's Allowance, the Winter Fuel Payment charge, student loan plans, and the return's closing boxes.

Filing a prepared return: the pre-flight gates and HMRC's own validation rules with Go to links, attachments, the Gateway login, the declaration, the three outcomes of a submission, and the history with its correlation IDs.

Accepted years lock; Reopen for amendment files a replacement return. The amendment deadline, the waiting-for-HMRC lock, rejections, and chasing stuck submissions.

Why a line in the accounts can be a pound away from the trial balance, and when you need to act.

Build the firm's working paper checklist from a ready-made pack, then add, edit, reorder and mark questions as required.

Answer the firm's checklist, move the file through its stages, keep track of every working paper in the firm and print the report.

How filing VAT for clients works in Tax Optimiser - what you set up once for the firm and what you do for each client.

The Details step: partnership name and live-checked UTR, boxes 3.1/3.2, period and start/cessation dates, the accounting basis and declarations, the page 2 questions and box 3.116.

Boxes 3.99 to 3.115: assets, liabilities and the partners' accounts, with all three totals calculated and a built-in way to check the sheet balances.

How quarterly figures get into Tax Optimiser: uploading a spreadsheet, the full and consolidated example templates, and mapping your own cells.

Sending a quarterly update: reading the values, confirming the declaration, and amending a quarter after it has gone.

The end-of-year additions - dividends, foreign income, pensions, reliefs - that complete the year before your tax is worked out.

How accountant firms pay for year-end filing: Active and Dormant credits, the packs, exactly when a credit is used, and the purchase and consumption history.

Add free credits with a gift code, and earn credits by sharing your firm's referral code.

Opening a client's first Self Assessment year, choosing the return's pages, the pre-filled personal details and the client-record check, the deadline chip, HMRC notes and help links, hidden pages, and the save-as-you-go model.

Square off a penny of rounding, or change how a balance is shown, without touching your bookkeeping.

What working papers record in Tax Optimiser, how a firm switches them on, and what appears on screen once they are.

Interest a company receives is a non-trading loan relationship credit, taxed in CT600 box 170 after netting against interest paid. When Tax Optimiser picks it up for you, when it does not, and how to fill in the Non Trade Credit grid.

HMRC rejected the CT600? What errors 3304, 1611, CTISS002 and an authentication failure mean, why they happen and how to fix each one.

Connect your firm's Zoho Sign account and send accounts, CT600s and SA100s to clients for e-signature. Signed copies and approval dates come back automatically.

Generate a Sodium API key, paste it into your firm settings, pick your practice, and sync your limited-company clients into Tax Optimiser in one click.