Unless otherwise agreed by the parties, a contract without the signature of one party is generally invalid. The contents of the contract are legal, and the signing of the contract is the true intention of both parties. If one party of the contract has not signed it, but both parties have sealed it or both parties have fulfilled the main obligations of the contract, the contract is valid. If the above conditions are not met, the contract is invalid.

1. Only one party signs or seals the contract. If one party (whether signed or sealed) fulfills the main obligations of the contract and the other party accepts it, the contract is established, regardless of whether the recipient has also fulfilled the corresponding obligations;

Only one party signs or seals the contract. If one party (whether the signatory or the seal party) performs the main obligations of the contract, but it is not accepted by the other party, the contract is not established;

3, only one party signed or sealed the contract, but both parties failed to fulfill the main obligations of the contract, the contract is not established;

4. If both parties fail to sign or seal the contract, one party has fulfilled the main obligations of the contract and the other party has accepted it, and the contract is established, regardless of whether the recipient has also fulfilled the corresponding obligations;

5. Neither party has signed or sealed the contract, and if one party has fulfilled the main obligations of the contract but has not been accepted by the other party, the contract is not established;

6. Neither party has signed or sealed the contract, and neither party has fulfilled the main obligations of the contract, so the contract is not established.

If this contract is a written contract with only the signature of Party B, but not the signature and seal of Party A, this contract is invalid.

If the contract is electronic, a confirmation letter must be signed in advance, otherwise the contract will be invalid.

Since it is a contract, it needs to be signed by both parties.

legal ground

Article 490 of the Civil Code of People's Republic of China (PRC): If the parties conclude a contract in the form of a contract, the contract is concluded when the parties sign, seal or fingerprint it. Before signing, sealing or fingerprinting, one party has fulfilled its main obligations, and the contract is established when the other party accepts it.

A contract shall be concluded in written form as stipulated by laws, administrative regulations or agreed by the parties. If the parties do not do this in writing, but one party has fulfilled its main obligations and the other party accepts it, the contract is established.