How To Write A Memorandum Of Understanding Letter . or i'm writing to request. How to write letter of understanding? Mou Template Database Letter Templates from diabetescured.biz Before deciding to write a memorandum of understanding with another party, make sure you know what it is—a formal document outlining a bilateral agreement sample between two parties, showing a framework for them to work with together but generally lacking the legal and binding features. Acceptance of the offer 3. It is a safer and more formal agreement compared to a word of mouth or ‘gentleman’s agreement.’.