A mortgage payoff letter can come in two forms. One form tells borrowers the remaining principal amount and interest they have to pay to close out the loan.Create a Loan Payoff Letter online and download it as a PDF or Word document. Customize and print a blank Loan Payoff Letter for free. A payoff letter provides instructions on how to pay off a loan with a lump sum before the loan term ends. Learn how payoff letters work. Mortgage or car loan.