Stepbystep guide on how to write contracts for leases, business partnerships, and employment contracts. Under Illinois law, an acceptance occurs if the party assented to the essential terms contained in the offer (Klein v.Klein, 2017 IL App (1st) 153393-U, ¶ 23. A legally binding contract must include an offer, acceptance, consideration, and intent to create legal relations. Read about the legal terms and disclosures you must add to an Illinois real estate purchase agreement. Learn what required information you must include.