Affidavit of Check Forgery - Complete, print, sign and mail this form to Star One Credit Union per instructions below. I am first duly sworn and state I am: Name.If your "signature" is on the affidavit and you didn't sign it, then someone probably forged your signature. An affidavit of forgery is an official declaration that a fraudulent act was committed. It should be completed, notarized, and sent to notify institutions. Affidavit of Forgery.