Legal basis: Article 490 of the Civil Code of People's Republic of China (PRC). If the parties conclude a contract in the form of a contract, the contract shall be established when both parties sign or seal it. There is no clear boundary between the seal and the official seal of a contract. However, this does not mean that signing the contract with the special seal of the contract takes effect, and signing the contract with the official seal does not take effect. In fact, the company's special seal for contracts and the company's official seal have legal effect when signing contracts on behalf of the company.