Learn how to write effective fundraising letters that inspire more support from donors. Explore best practices and templates in this comprehensive guide.Include the nonprofit's EIN so the the donor can to check the charity's tax-exempt status with the IRS. In this post, I'm breaking down how to write a donation letter. Please complete the enclosed Auction Donor Form and return in the enclosed envelope. There are many other reasons to send a receipt after receiving a donation. • Put up a fundraising goal. Acknowledgment of "no goods or services were provided as part of this donation.