Who Can Sign - For partnerships, only general partners can sign a contract, not a limited partner. For LLC's, a managing member or a hired manager can sign. For corporations, the company's president or chief executive officer is presumed to have the authority to sign. For an organization or association, a board president would have the authority, but may require a vote of the governing board to approve the deal.
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.