As a general rule, oral contracts are enforceable contracts and create a binding agreement between the parties so long as they are proven to contain all of the elements required under contract law (i.e. offer, acceptance, and consideration).
There are a few ways to prove the existence of these elements, and in turn, that there is a valid contract. These ways include, but are not limited to, presenting evidence of payments or performing services the contract called for. The burden of proof will be on the party seeking to enforce the contract.
There is an exception to the general rule that oral contracts are enforceable. This exception comes in the form of the Statute of Frauds. The Statute of Frauds requires that certain contracts be made in writing. The five types of contracts that are required to be made in writing are: (1) marriage (2) suretyship (3) contracts longer than one year (4) contracts made for the sale of goods over $500, and (5) contracts made for the sale of land.