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.

therefore, the power of attorney is invalid unless it is signed by myself.

power of attorney, also known as agency certificate. It is a certificate made by the principal, which proves the agent's right of agency and shows the scope of its authority. The power of attorney only exists in the entrusted agency, and there is no power of attorney in the legal agency.

the entrusted agent must have the authorization, and the principal will grant the agency to the agent, so that the agent has the right to perform civil legal acts on behalf of the principal. The authorization of principal-agent is an essential act. The principal and the agent should first sign a written contract and according to this contract, the principal will issue a power of attorney to the agent.

The contents of the power of attorney shall include:

1. The name of the agent, which may be a natural person, a legal person or an unincorporated organization;

2. Agency matters refer to the scope of civil legal acts authorized by the principal to the agent. According to different agency matters, agency matters can be divided into general agency and special agency;

3. Authority, the authority of agency is within the scope of agency matters, and what decisions can be made. Beyond the scope of the agency's authority, it constitutes an unauthorized agency beyond the agency; There is no clear agency matters and agency authority as agency matters and authority is unknown.

4. Time limit, that is, the starting and ending time of agency right;

5. The principal's signature or seal indicates who authorized the agent.

About the difference between power of attorney and contract. A power of attorney, also called a certificate of agency, is a written document that proves that an agent has the power of agency. A power of attorney is different from an entrustment contract:

(1) A power of attorney is an authorized act and a manifestation of a unilateral legal act; The entrustment contract is the basic legal relationship of authorization, but it is a legal act of both parties, and the principal issues a power of attorney according to the entrustment contract;

(2) once the power of attorney is issued, it will have the effect of authorization immediately, and the entrustment contract needs to be agreed by both parties;

(3) The power of attorney can directly prove the existence of the power of attorney. It doesn't matter whether there is an agency contract, but the existence of the agency contract can't prove the existence of the power of attorney.

Legal basis:

Article 163 of the Civil Code

Agency includes entrusted agency and legal agency.

the entrusted agent shall exercise the agency right as entrusted by the principal. The legal agent shall exercise the power of agency in accordance with the provisions of the law.