You can create two sections for signatures below your valediction. A formal letter follows a specific format and uses formal English language.Keep reading to find out how to write formal letters. I, the undersigned, applying for probate and for letters in the above estate, being first duly sworn, say that: 1. In this lesson, you will learn what an affidavit is and how to format one. You'll also review a sample template that can be used to construct an affidavit. How to fill out the Sample Letter of Agreement for Speakers? 1. Enter the date and speaker's name. 2. Follow the steps below to craft an effective signon letter and gather lots of signatures to help sway decisionmakers. There are many things in life that are out of our hands.