An affidavit is a sworn statement signed under oath. Learn how affidavits can be used in your case in this mini guide.An affidavit is a document where a person makes factual assertions, which they swear to be true and correct. Affirmation: A solemn and formal declaration under penalties of perjury that a statement is true, without an oath. Affirmed: Upheld, agreed with (e.g. An Affidavit is simply a written, notarized sworn statement. Written statement of facts; the person who signs the affidavit swears an oath that the information given is true. 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. Affidavits are legal documents which contain written sworn statements.