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. Learn how to create a mortgage gift letter template to ensure a smooth homebuying process with your gifted funds with 6 samples.A gift letter is an important, formal, legal piece of documentation that can help explain that a (usually rather large) sum of money was gifted to you. The goal of a gift letter is to provide the lender with proof of where the funds came from. The person gifting the vehicle must complete a sales tax exemption form (MVU-24). A mortgage gift letter is a document that helps satisfy the requirement that a borrower's down payment funds come from legitimate sources.