How To Write A Letter Contributing To A Memorial Fund . Tell the reader if you are giving the gift in someone's honor or if there are any restrictions or stipulations on its use. A letter accompanying a financial donation is a formal letter written to the organization or cause where or for which one has donated an amount of money or made a contribution. 10+ Sample Donation ThankYou Letters DOC, PDF Free & Premium Templates from www.template.net [keep it short and avoid caps and exclamations]: The reader should directly be addressed in the letter. It can include a line about where to send donations.