What is a Unique Taxpayer Reference if I register for Self Assessment in the United Kingdom?

GOV.UK says you get a Unique Taxpayer Reference when you register for Self Assessment or when you set up a limited company. It is a 10-digit number. It may be called a tax reference. You usually receive it by post about 15 days after you register. It takes longer if you live overseas. You can find an individual number in your Personal Tax Account, in the HMRC app, or on earlier letters from HMRC. Confirm on the official page.

Continue on GOV.UK