Oral contract is formed by verbal agreement like word of mouth and comes about when two people speak to each other. Written agreement assures that both the parties know the exact terms of the contract and provide proof of the agreement. It is better to have a written agreement since there are less chances of understanding about the terms and conditions of the agreement. A written agreement contains the identity of the parties, identification of the subject matter and terms of agreement and a statement of consideration. I think it is better to start the project on written agreement. It gives a legal agreement between you and the other party. Written agreement provides a proof of what was the agreement between you and the other party. It prevents from the future misunderstanding or disputes by making the agreement clear since its inception. It also reduces the risk of the disputes regarding the responsibility, timeframe. It also specifies how the contract can be ended.