Client sign-up process

Step 1: check whether the client needs to join

A client needs MTD for Income Tax if they are registered for Self Assessment, have self-employment or property income, and qualifying income is above the relevant threshold. Phased start dates:

• 6 April 2026 — above £50,000 (based on 2024/25 return)
• 6 April 2027 — above £30,000 (based on 2025/26 return)
• 6 April 2028 — above £20,000 (based on 2026/27 return)

Qualifying income is grossself-employment and property income before expenses. A partner's share of partnership profit does not count towards the mandation threshold (it still belongs on the year-end tax return). Partnership mandation dates are still to be confirmed.

Step 2: check exemptions

Some clients are automatically exempt or deferred; others must apply. If you can use compatible software and submit on the client's behalf, they may not need a digital exclusion exemption at all.

Step 3: choose software before sign-up

HMRC says to choose compatible software before sign-up. It must support digital records, quarterly updates, and the year-end tax return for all income sources you need to report.

If the client keeps records in spreadsheets, bridging software connected to those records remains a valid HMRC route. Where more than one product is used, the hand-off must be digital — not manual re-keying between systems. Only one product can make each separate submission to HMRC.

Step 4: confirm ASA authority

The client must be registered for Self Assessment and must have submitted a tax return in the last two years. If you hold Self Assessment authority, add it to the ASA if needed. If not, use the digital handshake first.

Step 5: gather details HMRC will ask for

Full name, date of birth, National Insurance number; for sole traders, business name, address and nature of trade; for each active self-employment or property source, business start date (or property income start if within the last two tax years); and the tax year they will start using MTD. Add any missing income sources if the client has more than one.

Step 6: sign up through the agent route

Use HMRC's agent sign-up service with the same credentials you use for the ASA. Do not use the individual taxpayer route when acting as agent. HMRC checks eligibility from the details you provide. Sign-up by API has been ruled out for security reasons — treat sign-up as an individual operational process, not a one-click migration.

What happens next

Keep digital records and send quarterly updates through compatible software. Quarterly updates are summaries of income and expense categories — not extra tax returns — and do not require accounting or tax adjustments before submission.

At year-end, finalise the client's tax position and submit the tax return or final declaration through compatible software. Do not plan around a separate End of Period Statement step — HMRC removed that from the current MTD design.

For clients required from 6 April 2026, HMRC will not apply penalty points for late quarterly updates in the first year (2026/27). That softening does not remove penalties for late tax returns or late payment.

Related: Adding client authorisations · Digital readiness checklist