Get Set Up With HMRC

Do it yourself

• Apply for the Agent Services Account online, once your AML supervision is registered, because HMRC asks who your supervisor is.
• Note that from 18 May 2026 you can no longer apply by post for Self Assessment or Corporation Tax agent codes; that route is now online through the ASA.
• Link any older agent accounts you already hold to the ASA.
• Store your ASA credentials securely, because this login is the master key to your clients’ data.

Do it yourself

• Obtain the agent codes you need through the ASA: Self Assessment, Corporation Tax, VAT and PAYE.
• Authorise each client with the right method: the digital handshake in the ASA, where for VAT the client completes within 21 days; an authorisation code posted to the client, which expires after 30 days; or a 64-8 for some services.
• Send clients clear instructions so they complete their side quickly.
• Track authorisation status per client per tax, so nothing stalls at a deadline.

Do it yourself

• Know that MTD for VAT is already mandatory for all VAT-registered businesses regardless of turnover, and has been since April 2022: records digital, returns via compatible software, and the old portal closed.
• Map the MTD for Income Tax Self Assessment timeline: April 2026 for qualifying income over £50,000, April 2027 for over £30,000, and April 2028 for over £20,000, where qualifying income is combined gross self-employment plus property income.
• Note what is out of scope: partnerships and companies are not in MTD ITSA yet, and MTD does not apply to Corporation Tax.
• Identify which of your first clients cross each threshold, and when, so you onboard them onto compatible software early.
• Confirm the current thresholds and dates on GOV.UK, and read HMRC’s Making Tax Digital guidance, before planning any client’s move. This is a signpost, not advice on an individual client’s obligations.