The legal effect of the contract has nothing to do with whether the contract seal has a number or not. Although the contract seal is not numbered, as long as the contract seal is the legal seal of the unit, both parties to the contract have considerable capacity for civil conduct, the meaning is true, and the contract content conforms to the legal provisions, the signed contract is valid.

Stamping a contract with a contract seal means that the parties to the contract affix their own contract seal to the written contract reached through consultation. For the parties to a contract, the special seal for the contract is affixed to the contract, indicating the completion of the contract offer and acceptance stage and the final confirmation of the rights and obligations of both parties, thus confirming that the contract is established through consultation between both parties and has legal effect on both parties, and the parties should exercise their rights and perform their obligations according to the contract.

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.

Article 489 An acceptance to make an immaterial change in the contents of an offer is valid, unless the offeror raises an objection in time or the offer indicates that the acceptance shall not make any change in the contents of the offer, and the contents of the contract shall prevail.

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.