Written Contracts: A written contract is usually pleaded by setting it out in its entirety in the body of the complaint or by attaching a copy. The other method of pleading is by alleging the making of the contract, and
then alleging the substance of its relevant terms. “A written instrument is presumptive evidence of a consideration.” (C.C.1614.) Therefore, it is not necessary to plead the existence of consideration to support the contract.
Oral Contracts: If oral, the exact words used can seldom be correctly alleged, and are evidentiary in nature. Hence, the oral contract is pleaded according to its legal effect. But the complaint is subject to a general demurrer if the allegations fail to show the nature of the contract with certainty.
Implied Contract: An implied in fact contract arises from conduct, without express words of agreement. Accordingly, “only the facts from which the promise is implied must be alleged.”