Acting for clients under MTD for Income Tax: the agent services account, authorisation and sign-up

acrenvo.com/guides/mtd-acting-for-clients-as-an-agent, last reviewed 25 October 2026

Before an agent can keep a client’s Making Tax Digital (MTD) for Income Tax going, three things need to be in place: an agent services account, the client’s authorisation and the client’s sign-up, in that order.

Amara is fictional. Amara runs a small practice with one assistant, and most of its clients are landlords and sole traders whose Self Assessment returns Amara has prepared for years. Several of them now need Making Tax Digital (MTD) for Income Tax, and Amara wants to be sure the practice is set up properly before their first quarterly updates fall due. This guide follows HMRC’s own steps for agents, so that a practice like Amara’s can see what has to be in place and in what order.

HMRC’s steps for agents

HMRC sets out the agent’s route through MTD for Income Tax as a sequence.

1. Work out your client’s qualifying income
2. Find out if and when your client needs to use Making Tax Digital for Income Tax
3. Apply for an agent services account
4. Add your client authorisations
5. Get compatible software
6. Sign up your client for Making Tax Digital for Income Tax
7. Use Making Tax Digital for Income Tax

The first two steps are about the client’s income and timing, which the main MTD guide covers. This guide picks up at the account, the authorisations and the sign-up.

The agent services account

Everything for MTD runs through one account. You will need an agent services account to use Making Tax Digital for Income Tax. It is the same account HMRC now uses to register tax advisers, so the conditions in the guide to registering as a tax adviser apply to it.

Amara’s assistant needs access too. GOV.UK’s page on applying for the account says that if your business uses services in the agent services account, you should create a Government Gateway user ID for each member of staff and set permissions to control their access to services and clients.

Bringing existing clients across

For clients Amara already acts for, the authorisation the practice holds for Self Assessment does most of the work. Your existing client authorisations for Self Assessment are recognised for Making Tax Digital for Income Tax. Check if the authorisations have been added to your agent services account, and use Self Assessment agent codes to add any authorisations you need to.

HMRC’s table of authorisation routes gives two for MTD for Income Tax: apply using the digital handshake or add Self Assessment authorisations from your HMRC online services account to your agent services account. Clients who have already accepted a digital handshake need nothing more. You do not need to do this if your clients have already authorised you for Making Tax Digital for Income Tax through a digital handshake.

New clients and the digital handshake

A new client has to authorise the practice through the digital handshake. To get authorised using the digital handshake, you need to send an authorisation request.

1. Sign into your agent services account.
2. Select ‘Ask a client to authorise you’.
3. Enter your client’s details and follow the steps to get an authorisation request link on the final page.

There are two things to watch here. You need the sign in details for the agent services account itself, because GOV.UK says you will not be able to get authorisation using the sign in details you have for HMRC online services. And the link does not last. The link will expire after 21 days. If your client does not use the link before it expires, you’ll have to start the authorisation process again.

To check whether a client has responded to your authorisation request link, go to the ‘Manage your authorisation requests from the last 30 days’ page in your agent services account. Once your client has approved your authorisation request, you will be authorised to deal with HMRC for them.

The client’s side of the handshake, including what they see before they agree, is set out in the guide for clients authorising an agent, which can be a useful link to send them.

Signing a client up

Authorisation and sign-up are separate steps, and they happen in that order. Remember, you will need to be authorised to act on your client’s behalf before you sign them up for Making Tax Digital for Income Tax. If you are not authorised by your clients, you cannot sign them up for Making Tax Digital for Income Tax.

Adding authorisations does not do the sign-up for you. You will still need to sign up each client to use Making Tax Digital for Income Tax using the sign up service. To sign up your client for Making Tax Digital for Income Tax, they must:

• be registered for Self Assessment
• have submitted a tax return in the last 2 years

Main and supporting agents

MTD for Income Tax lets a client have more than one agent, which suits a bookkeeper and an accountant sharing a client. GOV.UK gives this example. For example, a bookkeeper might complete quarterly updates. In this scenario, they are a supporting agent. An accountant might finalise the client’s overall tax position and submit their final tax return. In this scenario, they are a main agent.

A client can only have one main agent at a time, but any number of supporting agents. The supporting agent’s access is narrower. For example, supporting agents cannot:

• set up a direct debit for the client
• change how a client wants to be contacted by HMRC
• view all sources of a client’s income for Self Assessment
• finalise a client’s overall tax position
• submit a client’s tax return
• view a client’s tax calculation

The work still has to come together at HMRC’s end. If multiple agents are involved in the same business, you must make sure one combined update to HMRC is:

• sent for each update period
• submitted for the tax return after any adjustments

For Amara, that means agreeing with any other agent which of them sends each update, and checking that the software allows it. The guide to MTD software for agents covers what to look for.

Questions agents ask about acting for MTD clients