UTR stands for Unique Taxpayer Reference. It is a 10-digit number that is assigned to individuals and businesses by HM Revenue and Customs (HMRC) to identify them for tax purposes. The UTR is used to keep track of an individual's or business's tax obligations, including filing tax returns and paying taxes.

The UTR is a unique number and is different for each taxpayer. It is used as a reference number on various documents, such as tax returns, tax statements, and correspondence with HMRC.

If you are a new taxpayer, HMRC will automatically issue you a UTR when you register for Self Assessment or any other tax-related service. If you are an existing taxpayer and do not have a UTR, you can apply for one online through the HMRC website.

It's important to keep your UTR safe and secure, as it is a key piece of information for your tax affairs. You may need to provide your UTR to your accountant or tax advisor, as well as to HMRC when filing tax returns or making payments.