What do you need to include in your donation acknowledgment letter? A gift acknowledgment letter weaves together your nonprofit's appreciation, engagement, and compliance efforts following a donor's generosity.A donor acknowledgement letter should include a few specific items to assist the donor and help your organization comply with IRS regulations. Want to learn how to write and structure donor acknowledgment letters? Check out these tips and sample letters to make a greater impact. Gift acknowledgement letters are important for two reasons. First, they provide proof so donors can claim a US tax exemption. Donation acknowledgment letters are more than just a donor tax receipt. There are certain items to include for tax purposes. Ten-trip tickets are valid for ten one-way trips.