general rules of civil law
Article 64 The types of agents include entrusted agents, legal agents and appointed agents.
The entrusted agent shall exercise the power of agency according to the entrustment of the principal, the legal agent shall exercise the power of agency according to the provisions of the law, and the appointed agent shall exercise the power of agency according to the designation of the people's court or designated unit.
Article 65 A civil juristic act in the form of entrustment may be entrusted in writing or orally. If the law requires it to be in writing, it shall be in writing.
The written power of attorney for entrusted agency shall specify the name, agency matters, authority and time limit of the agent, and shall be signed or sealed by the principal.
If the power of attorney is unclear, the client shall bear civil liability to the third party, and the agent shall bear joint liability.