A 10day payoff refers to the time it takes for your new lender to pay off your old loans during a refinance. 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. 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. Calculate how quickly you can pay off your mortgage if you increase your monthly payment. Submit a Payoff Request Form via email or fax. Creating a payoff letter is essential to any loan or mortgage repayment process. Our free templates and this guide can help you get started. Alternatively, your lender may have a form you must fill out.