The IRS taxes gifts made over a certain dollar amount. A gift letter must contain the donor's name, the gift's value, confirmation that the gift is not to be repaid, and the donor's signature.Form 4506T has multiple uses and special attention must be taken when completing the form for a gift tax inquiry. What is a gift letter? A gift letter is a document that certifies the funds you're receiving for your down payment are a gift, not a loan. Let's look at the tax implications of receiving a gift for your down payment and how you can minimize your risk. Gift Letters And Taxes. What Are The Tax Implications of a Gift Letter?