When someone offers to help you make a down payment on a house, your lender will require a gift letter for a mortgage. Here's what it includes.A down payment can be hard to come by. One option is to be gifted the money, but this has certain requirements, such as a gift letter. Your bank needs a written letter to prove that any money gifted to you to help buy a house is in fact a gift, not a loan. You can often use money you are given to help fund the down payment or closing costs of buying a home. You will need a gift letter when you do. A gift letter is a note from a donor to your lender regarding cash funds for your mortgage down payment. Down payment gifts, while common, must be documented accurately in order to be applied to a mortgage. California mainly uses two types of deeds: the "grant deed" and the "quitclaim deed.