When a contract is signed by a unit, it is generally signed by the legal representative of the legal person or stamped with the official seal of the unit; when a contract is signed by a natural person, it is generally signed by the natural person who entered into the contract or stamped with his or her name. Article 490 of the "People's Republic of China" and the Civil Code: If the parties conclude a contract in the form of a contract, the contract shall be established when both parties sign, seal or fingerprint the contract. Before signing, sealing or fingerprinting, one party has performed its main obligations and the contract is established when the other party accepts it. Laws and administrative regulations stipulate or the parties agree that a contract should be concluded in written form. If the parties do not use written form but one party has performed its main obligations and the other party accepts it, the contract is established.