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 10 day payoff is crucial to getting your old loans paid off during a refinance. Learn how it works from start to finish. 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 Satisfaction of Security Instrument is a document that shows an individual has paid a deed of trust or a mortgage in full. This is a standard form of payoff letter. A payoff letter shows the remaining balance on your mortgage, including fees, interest, etc. Learn more about what a payoff quote is and how to request one.