What do you need to include in your donation acknowledgment letter? A donation acknowledgment letter (sometimes called a donation receipt or thankyou letter) is an email or paper that recognizes a charitable contribution.Organization's name; Donation description. If it is cash, give the amount. Organizations stretch that time period out to 18 or 24 months. • Annual appeal: Either the only fundraising letter, or the most important fundraising letter,. Complete your specific application, get it signed and notarized, and pay the required fee. See specific instructions for each application type. When you donate materials please fill out a Gift Record Form so an acknowledgement letter is received.