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. Donation acknowledgment letters are more than just a donor tax receipt. There are certain items to include for tax purposes. Discover how to craft donor acknowledgment letters that resonate. Access templates and best practices for donor engagement. If you are expecting a gift item, please look for it under separate cover from the acknowledgement letter, and allow up to eight weeks for it to arrive. Use this page to quickly find answers to common questions about The Nature Conservancy. No experience is necessary.