Dealing with HMRC – guidance

Registering your client's business with HMRC

Find out how to use the online tax registration service to register your client's business with HMRC.


When a client sets up a business they must register it with HM Revenue & Customs (HMRC) for tax purposes.

The easiest way to do this is online. HMRC’s online tax registration service enables your client to register for Self Assessment, PAYE (Pay as You Earn) and VAT and to tell HMRC if your business is liable to Corporation Tax, (if you haven’t done so already). You can also use this service to register your client’s business with HMRC on their behalf.

What is HMRC’s online tax registration service

You and your client can register their business online for tax purposes. One of the benefits of doing this online is that you can register for more than one tax at the same time.

To register a business on behalf of your client, you must be set up as an agent on the Government Gateway - but you don’t need to have a formal agent authorisation for your client in place - online or paper form 64-8 - to use this service.

But please note: to formally deal with HMRC on a client’s behalf, you must go through the agent authorisation process.

Go to the Government Gateway website.

Get started with HMRC Online Services for agents.

Alternatively, your clients can submit their own registration - or start the online process and set you up as a delegate to review their submission - before they send it to HMRC.

If your client submits the registration, the business will automatically be set up for the relevant online service(s) with the option to opt out for Self Assessment. If you register on their behalf - they will need to sign up for the online service separately.

Find out more on how to set up client authorisations.

Register your client’s business with HMRC.

Self Assessment

Your clients should register for Self Assessment if they need to complete a tax return. How they register depends on their circumstances.

Read more about registering for Self Assessment.

Corporation Tax

If your client sets up a new limited company or unincorporated organisation, they must tell HMRC that it’s liable for Corporation Tax within three months of it becoming ‘active’ - for example, starting in business, trading or receiving income.

Follow the link below to read about how limited companies can do this online and the different process that unincorporated organisations need to follow.

More about starting a company or organisation and Corporation Tax.

PAYE for employers

Generally, the easiest way to register as an employer is online, but there are some exceptions when HMRC asks you to use another method. These include:

  • limited liability partnerships
  • trusts
  • clubs and societies
  • limited companies with more than nine directors
  • partnerships with more than ten partners

Learn more about how to register as an employer.


Most applications for VAT registration can be completed online. Those that can’t include businesses applying for exception from VAT registration or registering VAT divisions. If you submit an application for VAT registration on your client’s behalf:

  • you will receive confirmation through the ‘Customer communications’ section on the ‘Your HMRC services’ page
  • the certificate of registration will be sent to your client through the post

Read more about how to register for VAT.

Further information

Login to HMRC Online Services for agents.

Find out more about how to use HMRC Online Services.