An affidavit is a written statement made under oath or affirmation. It's used as evidence in legal proceedings.An affidavit is more than just a legal document; it's a sworn statement that holds significant weight in the eyes of the law. Fill in an Affidavit (PDF, 44 KB) confirming that you have never been indicted and sentenced for a felony of any kind. An affidavit is a written statement made under oath that is typically used in legal proceedings. Learn their purpose, when to use, and how to write. See also Affidavit of Support.