The taking of an acknowledgment consists of positively identifying the signer of a document. An acknowledgment is one of the most common types of notarial acts, but it often confuses Notaries.Here are 5 steps to performing an acknowledgment. An Illinois notary acknowledgment form is a written authentication from a notary that the signature on a document belongs to the signer. This article and video will show Notaries to fill out each part of a notarial certificate, and common mistakes to avoid. This 5-step guide will teach you how to notarize a document that requires an acknowledgement (the most common notarial act). To fill out this form, first ensure you have the required identification and documentation. Next, accurately enter the information needed for the notarial act.