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. The person who gave you the money must write and sign the gift letter as well as provide their personal information.How to Write a Gift Letter for a Mortgage Down Payment? A short letter like this sample gift letter will cover all of the requirements your lender needs. If you go through a bank they will provide the gift letter form to you to get completed. If someone provides a handwritten letter it is filed away. A gift letter is a note from a donor to your lender regarding cash funds for your mortgage down payment. Learn about gift letter requirements The last item is the most important element of the gift letter. The letter should state that the person giving you the money is not getting something of value in return, such as an ownership stake in the property.