Round, red style.

The official seal of an advertising company is round and red, with the name of the company engraved on it.

Article 490 of the "People's Republic of China and Civil Code" If the parties conclude a contract in the form of a contract, the contract shall be established when both parties sign, seal or fingerprint. Before signing, sealing or fingerprinting, one party has performed its main obligations and the contract is established when the other party accepts it. Laws and administrative regulations stipulate or the parties agree that a contract should be concluded in written form. If the parties do not use written form but one party has performed its main obligations and the other party accepts it, the contract is established.