Contract is an official agreement.A contract has six important elements so that it will be valid which is offer, acceptance, consideration, intention to create legal relation, certainty and capacity.Contracts can be written by using formal or informal terms, or entirely verbal or spoken.It is a promise made between two or more parties that which allow the courts to make judgement.If the main elements are not in contract, it would be an invalid contract.It could be written or even be in oral.