SHAHVEZ MEMON

Hello I have been trying to log into my tax account via gate away id and have been getting message that my details does not match and it s been months like this. Yesterday, I called HMRC for some tax code clarification and have been told that my date of birth is incorrect on the system and i need to send document to get it corrected Please can I kindly be guided about the process, where to send the document and does the original driving licence will be sufficient ? and should i include a signed return post envelope in the post as well for return of the document and how will be notified once the changes have been made? I will be very grateful for the response thanks