Legal analysis: If it is an entrusted agent, the signature is valid. If the power of attorney is in written form, the power of attorney shall specify the agent's name, agency matters, authority and time limit, and shall be signed or sealed by the principal. If the parties enter into a contract in the form of a contract, the contract shall be established when the parties sign, seal or press their fingerprints.

Legal basis: Civil Code of People's Republic of China (PRC).

Article 165 If the power of attorney is in written form, it shall specify the name of the agent, the matters to be represented, the authority and the time limit, and shall be signed or sealed by the principal.

Article 490 Where the parties conclude a contract in the form of a contract, the contract is formed when the parties sign, seal or fingerprint it. Before signing, sealing or fingerprinting, one party has fulfilled its main obligations, and the contract is established when the other party accepts it.

A contract shall be concluded in written form as stipulated by laws, administrative regulations or agreed by the parties. If the parties do not do this in writing, but one party has fulfilled its main obligations and the other party accepts it, the contract is established.