What is the difference between a User ID and an Activation PIN?
User IDs and Activation PINs are similar 12 digit numbers so it is easy to become confused. A User ID is used to log in to HMRC’s Online Services. You should make a note of this number and keep it in a secure place together with your password. An Activation Code (also known as an Activation PIN) is used to activate a service that you have enrolled for. Once you have activated the service, and you are happy that you can successfully log in to it, you can safely discard this number.