With regard to real estate, a written contract is required, almost without exception. Generally speaking, an agreement to transact any interest in real estate must be in writing.

It is the contract which governs the entire transaction. It is a most important document. A lawyer should prepare the agreement, or where another real estate professional is involved, for example a licensed real estate sales person or broker, a lawyer should review it before it is signed. A contract is a binding commitment. Once it is signed it cannot be altered except by mutual consent of the parties.

An "option contract" however is not binding upon both parties, but instead upon just one. It is utilized when a purchaser wants to establish the legal right to buy real property, but isn’t certain as yet that he/she wants to be obligated.