Legal basis: Article 491 of the Civil Code of People's Republic of China (PRC). The parties conclude a contract by means of letters, data messages, etc. And a confirmation letter is required, 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.