The contract signed by the agent is valid. 1. If the party authorizes a third party to sign on his behalf, the contract is valid; 2. If the person signing on behalf of the party does not have the authority of agency, exceeds the authority of agency, or signs on behalf of the party after the authority of agency has been terminated, the validity of the signature is pending. Although the party is not aware of it, if the principal ratifies it later, the principal shall bear civil liability for the signing act; if it is not ratified, the person who signed on behalf shall bear civil liability; 3. If the signature is signed on behalf of The person (i.e. trustee or agent) is authorized to sign on behalf of the person being signed (i.e. principal or agent), or the person signing on behalf of others knows that someone else is signing on his behalf without denying it, then the signature is valid and the person signing on behalf shall bear legal responsibility; 4. If a third party signs in his name without the authorization of the party concerned, the contract will not have legal effect on the party concerned, and all consequences arising therefrom shall be borne by the person using his or her name. borne by the third party.