Creating a payoff letter is essential to any loan or mortgage repayment process. Our free templates and this guide can help you get started.A payoff letter template is a pre-made document used to inform a lender or creditor that a borrower has fully paid off their loan or debt. A mortgage lender might ask you to write a letter of explanation to better understand your finances when deciding whether to approve you for a loan. Are you about to payoff your mortgage?