The letter must explain who is gifting the money, where the donor's funds are coming from and the relationship between the donor and the recipient. We'll also show you how to write a gift letter with a gift letter template so you can help your donor prepare for underwriting.A mortgage gift letter is a simple but essential document that assures lenders the funds you received are a gift, with no repayment expected. This guide explains how to document gift funds for a mortgage and meet lender requirements. A gift letter needs to be from the person who gave you the funds, and they need to include information showing the gift doesn't need to be paid back. A mortgage gift letter is a document that helps satisfy the requirement that a borrower's down payment funds come from legitimate sources.