An affidavit is a written factual statement, voluntarily signed and sworn in front of a person authorized to administer oaths, such as a notary public.
An affidavit is based upon either the personal knowledge of the affiant or his or her information and belief. Personal knowledge is the recognition of particular facts by either direct observation or experience. Information and belief is what the affiant feels he or she can state as true, although not based on firsthand knowledge. An affidavit based on personal knowledge carries more weight than one based merely on information and belief.
A notary public or other official cannot take affidavits outside of the particular jurisdiction in which he or she exercises authority. The source of this authority must appear at the bottom of the affidavit. A notary, for example, would indicate the county in which he or she is commissioned and the expiration date of the commission. An official seal is not essential to the validity of the affidavit but may be placed on it by the proper official.
Courts often require that a litigant file an affidavit to support a motion. The purpose of the affidavit is to show that there is some factual basis upon which the motion is based. Affidavits are particularly used to support motions in emergency proceedings such as a hearing for the issuance of emergency child custody or for temporary restraining orders.
Sample affidavit forms are available at the Columbus Law Library's website at http://www.fclawlib.org/forms.aspx. These forms are not officially approved by the court.