A contract does not have to be signed by both parties to be valid. If one party has performed the main obligations of the contract before the signature of both parties, and the other party accepts it, and has gone through the approval and other procedures as the key elements of the contract, the contract will also come into force.
[Legal Basis]
In Article 143 of the Civil Code, civil juristic acts that meet the following conditions are valid:
（1） The actor has corresponding civil capacity;
（2） True declaration of intention;
（3） It does not violate the mandatory provisions of laws and administrative regulations, and does not violate public order and good customs.
