Have you recently settled a debt and are searching for a paid in full letter? Good news, we've got two free sample form letters below.If you ever need to prove that a debt is fully paid and can no longer be collected, then a paidinfull letter can be your best friend. Our guide will teach you how to write a letter of explanation, plus offers a free template to help you write one of your own. This program will help you write a letter that formally requests the money you are owed. This is called a Demand Letter. 1. In the sample letter, fill in your personal information.