As long as there is a real signature, it is valid. Generally speaking, it is OK to sign. It would be better if the signature was added with the fingerprint. If the parties conclude a contract in the form of a contract, they shall sign or seal it. If a party makes a handprint on the contract, the people's court shall determine that it has the same legal effect as the signature or seal.
 Legal basis:
 Article 490 of the Civil Code Where the parties enter into a contract in the form of a contract, the contract is formed when all the parties sign, seal or fingerprint. The contract is formed when one party has performed its main obligations and the other party has accepted them before signing, sealing or fingerprinting.
 A contract shall be concluded in writing as required by laws and administrative regulations or as agreed by the parties. A contract is formed when the parties fail to adopt a written form but one party has performed its main obligations and the other party has accepted it.