1. There are many cases of signing a contract. Generally speaking, contracts have legal effect only if they are signed by the parties, while some contracts are signed by others. If the agent is entrusted by others, it is generally not responsible;
2. If a contract is signed without a power of attorney, it shall be liable for the invalidity of the contract.
Under what circumstances can I sign it?
The signature can be signed as follows:
1. If authorized by the party concerned, it can sign on behalf of the party concerned, and signing on behalf of the party will enable the agent to establish an entrusted contractual relationship with the party concerned;
2. A contract concluded by the agent with a third party in his own name within the scope authorized by the principal, and the third party knows the agency relationship between the agent and the principal when concluding the contract, the contract directly binds the principal and the third party, unless there is definite evidence to prove that the contract only binds the agent and the third party.
Legal basis: Article 171st of the Civil Code of People's Republic of China (PRC).
If the actor has no power of agency, exceeds his power of agency or terminates his power of agency, he will still carry out the agency act, and it will have no effect on the principal without ratification by the principal. The counterpart may urge the principal to ratify it within 30 days from the date of receiving the notice. If the trustor fails to declare it, it shall be deemed as refusal to ratify it. Before the act committed by the actor is ratified, the bona fide counterpart has the right to revoke it. Revocation shall be made by notice. If the act committed by the actor is not ratified, the bona fide counterpart has the right to demand the actor to perform the debt or demand the actor to compensate for the damage he has suffered. However, the scope of compensation shall not exceed the benefits that the counterpart can obtain when the principal ratifies. If the counterpart knows or should know that the actor has no right to act as an agent, the counterpart and the actor shall bear the responsibility according to their respective faults.