Legal analysis: Unsigned contracts are generally invalid, but unsigned contracts take effect after one party has fulfilled its main obligations and the other party has accepted them. One party actually fulfilled the contractual obligations, and the other party accepted them, indicating that both parties have a * * * understanding of the contents of the contract, so the contract was established. Wechat signing the contract is valid. If the law requires the parties to conclude a contract by letter, data message, etc. They can ask to sign a confirmation letter before the contract is established. The contract was established when the confirmation letter was signed. As long as it does not constitute an invalid contract, the contract has legal effect. The parties to a contract have capacity for civil conduct, and the contract is signed by both parties voluntarily, which does not violate the mandatory provisions of the law and public order and good customs, and is effective.

Legal basis: Civil Code of People's Republic of China (PRC).

Article 490 Where the parties conclude a contract in 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 491 The parties entered into a contract in the form of data messages. It is also required to sign a confirmation letter, and the contract is established when the confirmation letter is signed. If the information of a commodity or service released by one party through information networks such as the Internet meets the conditions of the offer, the contract is established when the other party successfully selects the commodity or service and submits the order, unless otherwise agreed by the parties.