Signature and seal have legal effect. In actual civil activities, there are usually other evidences to prove it. Important civil activities are generally confirmed by seals, notarization and other means. In criminal or some civil activities, fingerprints are often added to prove that they are the same as signatures. In short, it is not a casual signature that has legal effect, but a signature is a kind of evidence and voucher to prove the expression of meaning. Generally speaking, this will do. If it is not enough, there are many other means.

People's Republic of China (PRC) Civil Code

Article 490 When concluding a contract, if the parties adopt the form of a contract, the contract is formed 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.

Article 502 A lawfully formed contract shall become effective upon its formation, unless otherwise provided by law or agreed by the parties.

In accordance with the provisions of laws and administrative regulations, if the contract should go through the approval procedures, such provisions shall prevail. If the failure to go through the formalities such as approval affects the effectiveness of the contract, it will not affect the performance of the obligation clauses such as approval and the effectiveness of relevant clauses in the contract. If the party that should go through the formalities for approval fails to perform its obligations, the other party may require it to bear the responsibility for violating its obligations.

The modification, assignment and dissolution of a contract shall be subject to the provisions of laws and administrative regulations, and the provisions of the preceding paragraph shall apply and shall be subject to approval.

Second, how to sign a contract is effective

1. General conditions for the contract to take effect: refers to the general conditions for the contract to have an effect. Any contract can be valid and established according to law only if it has general valid elements, including:

(1) The actor has corresponding capacity for civil conduct;

(2) the meaning is true;

(3) It does not violate the law or public interests.

2. Special requirements for the entry into force of a contract: it refers to the conditions under which a contract must have special requirements in addition to the general requirements for entry into force. The special entry into force of a contract is only a special entry into force of some contracts stipulated by laws and administrative regulations, and it is not universal.