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. A mortgage gift letter is a document that verifies that the gift money you receive is, in fact, a gift that you do not have to repay.Most lenders have a template for mortgage gift letters that you can download, fill out, sign and submit back to the lender. In Sacramento, call (916) 874-6334. 2. Determine What Type of Deed to Fill Out for Your Situation. That's why a gift letter is a requirement for gifted down payment funds. What are seasoned funds? It shows a mortgage lender that you're under no obligation to pay the money back. A gift letter for a mortgage shows your lender that you don't need to repay gift money toward your down payment. In most cases, documentation in the form of a gift letter will be required.