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.

Legal basis:

Article 165 of the Civil Code of People's Republic of China (PRC) * * * If the power of attorney is in written form, the power of attorney shall specify the name of the agent, matters of agency, authority and time limit, and shall be signed or sealed by the client.