Common forged documents include checks, contracts, wills, and identification cards. In Illinois, in its simplest terms, forgery can be understood as the knowing and willful falsification of signatures, documents, or objects.Free Consultation - Call (312) 902-3344 - This page covers the state legislation, punishments, examples and possible legal defenses concerning forgery. First, assuming they forged the signature on a document that obligates you to a contract, payment, etc. (2) Forgery is a Class 4 felony when only one Universal Price Code Label is forged.