A gift letter for a mortgage shows your lender that you don't need to repay gift money toward your down payment. A short letter like this sample gift letter will cover all of the requirements your lender needs.A mortgage gift letter is a simple but essential document that assures lenders the funds you received are a gift, with no repayment expected. A gift letter is a note from a donor to your lender regarding cash funds for your mortgage down payment. Use these stepbystep instructions for accepting a cash downpayment gift on a home, including a readytouse mortgage gift letter template.