The Unique Taxpayer Reference (UTR) is a number that HMRC uses to distinguish you for everything to do with your taxes. You naturally enroll for an UTR when you get set up for Self Assessment tax returns or dispatch a Limited Company. ... In your Self Assessment tax return.
The UTR number is the thing that HMRC use to distinguish you by and by with your tax commitments.
UTR numbers are consequently produced when you either enroll for self-assessment or when you set up a limited company. Your UTR number can be found on official HMRC archives (e.g. your SA250 'Welcome to Self-Assessment' letter) and on past tax returns.
Once you've been enrolled with an UTR, you can discover it in a couple of better places:
In your SA250 ("Welcome to Self-Assessment") letter
In your past Self Assessment tax returns
In the notice you got from HMRC to record a tax return
In your Statement of Account and any installment updates
When you are prepared to begin documenting your Self Assessment tax returns, you will be sent the SA1 shape from HMRC to sign – which is where you apply for an UTR number.