In this post, I'm breaking down how to write a donation letter. 1. Print the template on letterhead.In this article, we'll cover how to write a donation letter. Use one of our six sample donation request letter templates to get started. This is the simplest online donation form template that you can use without any code requirement and accept donations in the easiest way. This step-by-step guide will help you fill out the donation tax receipt and get things in order for tax season.