When you have a business where customers contract you to perform a service, you need a legally binding agreement to spell out of the terms and conditions of the business relationship. According to "All Business," a business agreement serves as a guide that all parties to the agreement must follow. Generally, one party draws up the agreement and both parties sign the it as an acknowledgment of the terms and conditions it contains.
Legal Contracts - Under state laws, only a few category of contracts must be in writing, such as a mortgage contract or contracts covering more than a year. It's still a good idea, however, to have a written agreement for business transactions beyond an ordinary sale of goods. There is no law requiring a lawyer to write your contract. If the transaction is relatively simple, the contract can also be simple. But you also have to pay attention to certain details to avoid issues arising later.