The person making an affidavit (the deponent) must sign the bottom of each page in the presence of an authorized person, such as a lawyer of Justice of the Peace. On the last page of the affidavit the following details must be set out (known as a jurat):
- The full name of the person making the affidavit, and their signature
- Whether the affidavit is sworn or affirmed
- The day and place the person signs the affidavit, and
- The full name and occupation of the authorized person, and their signature.
If any alternations (such as corrections, cross-outs or additions) are made to the affidavit, the person making the affidavit and the witness must initial each alteration.
Affidavits may be written in the first or third person, depending on who drafted the document. If in the first person, the documents component parts are:
- a commencement which identifies the affiant;
- the individual averments, almost always numbered as mandated by law, each one making a separate claim;
- a statement of truth generally stating that everything is true, under penalty of perjury, fine, or imprisonment,
- an attestation clause, usually a jurat, at the ending certifying the affiant made oath and the date; and
- signatures of the author and witness.
If an affidavit is notarized or authenticated, it will also include a caption with a venue and title in reference to judicial proceedings. In some cases, an introductory clause, called a preamble, is added attesting that the affiant personally appeared before the authenticating authority.
There is no standard form or language to be used in an affidavit as long as the facts contained within it are stated clearly and definitely. Unnecessary language or legal arguments should not appear. Clerical and grammatical errors, while to be avoided, are inconsequential.
The affidavit usually must contain the address of the affiant and the date that the statement was made, in addition to the affiant’s signature or mark. Where the affidavit has been made is also noted. When an affidavit is based on the affiant’s information and belief, it must state the source of the affiant’s information and the grounds for the affiant’s belief in the accuracy of such information. This permits the court to draw its own conclusions about the information in the affidavit.