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.We can send you a copy of your acknowledgement. Looking for an easy way to create fundraising letters? This guide and free templates empower you to effectively communicate needs and inspire support! Contact the foundation; a staff member will be assigned to guide the process. 2. Donor thank-you letters are the first step to retaining and cultivating your supporters. Learn how to craft incredible thank-you's with our guide!