An affidavit should contain a title, the affiant's identification commencement, the averments, the affiant's declaration of the averments' truthfulness and an attestation, according to SFGate. It should also feature a format that is familiar to the court.
Start the affidavit by writing a caption in case the affidavit is part of a case, as SFGate explains. In the caption, write the venue of the case at the center of the top of the page, and write the names of the plaintiffs and defendants below the venue on the left side of the page. Finalize the caption by writing the case number on the right side of the page, below the court venue. Write the word, "Affidavit" below the caption, and center the word. In the absence of the caption, write the word at the page's top.
After writing "Affidavit," identify the affiant with a commencement such as “Comes now Harry and states as follows:” and follow up with the averments, which are relevant claims to the case, notes SFGate. Separate and number each averment, and clearly identify any opinion averments. Conclude the averments with the statement “Further Affiant sayeth nought.” At the end of the averments, include a declaration that the claims are factual to the best knowledge of the affiant, and provide the affiant's signature line below the declaration.
Finally, state an attestation by a legal practitioner to affirm that the affiant made the claims under oath and identified himself, as SFGate instructs. Then, date the attestation before the affiant signs it.