A properly completed, notarized general affidavit form can be useful in legal proceedings. Here's how to make sure your affidavit is valid in Texas.My name is___________________________________________. I am of sound mind, 18 years of age or older, and competent to give this affidavit. Learn how to fill out an affidavit correctly with this comprehensive guide. Discover the steps, types, and when you might need an affidavit. Verify statements for legal matters and business transactions using our Texas general affidavit form template. We also learned the ten steps to formatting an affidavit, which are as follows: Step 1: Decide what the title of your affidavit will be. And I am 18 years of age or older. This document provides a comprehensive guide on how to fill out a general affidavit form.