THREE ESSENTIAL ELEMENTS OF A COMPLETE AFFIDAVIT
Three essential elements must be satisfied to constitute a complete affidavit. They are:
a written oath representing the facts as sworn to by the affiant;
the signature of the affiant; and
the attestation by an officer authorized to administer the oath that the affidavit was actually sworn by the affiant in the presence of that officer.
An affidavit typically includes a title or caption, signature of the affiant, the jurat, and the body of the instrument. An affidavit should also state the venue. The substance of the document makes it an affidavit. If the affiant is competent to testify to the contents of the affidavit at trial, then mere technical deficiencies do not render the affidavit improper.
An affidavit is not a “lawful affidavit” if:
the affidavit is signed outside the presence of an officer, or
no oath is administered.
An affidavit must state facts and at the same time it should affirmatively demonstrate how the affiant obtained personal knowledge of those facts. If the facts stated in the affidavit are untrue and outside the personal knowledge of the affiant, then the affidavit will become legally insufficient.
– See more at: http://affidavits.uslegal.com/elements-of-affidavit-generally/#sthash.IOJD1b7p.dpuf