Write only about things that are within your personal knowledge. I have personal knowledge of the facts in this affidavit, and, if called as a witness, could testify competently about them. 2.Use this form to swear under oath in writing to facts that you personally know. 1. Download the form and save it on your device. All Illinois Courts must accept these forms. Part One: the ID Theft Affidavit. This is where you report general information about yourself and the theft.