The purchase contract can be signed by others, but it needs a power of attorney notarized by the notary office.

Signing on behalf of the agency is an agency act in law, and its legal effect should be analyzed according to the specific situation:

1. If the signer (i.e. trustee or agent) is entrusted by the signer (i.e. principal or agent) to sign on his behalf, or if the signer knows that someone else is signing in his own name and does not deny it, the signature is valid and the signer shall bear legal responsibility.

2. If the person signing on behalf of the company has no power of attorney, exceeds the power of attorney or signs on behalf of the company after the power of attorney is terminated, the effectiveness of the act of signing on behalf of the company is uncertain. If it is ratified by the principal afterwards, the principal shall bear civil liability for the signature; Without ratification, the actor who implements the proxy signature shall bear civil liability.