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.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. Here's a step-by-step guide on how to write a Loan Payoff Letter: 1. This article outlines the fivestep process of making your final loan payment. Step 1: Request a payoff quote. Fill out the form below to request a loan payoff letter. If you have any questions, please contact Loan Customer Service at 1-800-677-6272 option 5, option 2. Complete this home equity line of credit application and simply drop off at any of our branch locations or mail to: Washington Savings Bank