The signature stamp can replace the signature, which can be correctly explained in the bidding documents. According to Article 490 of China's General Principles of Civil Law, if the parties conclude a contract in the form of a contract, the contract is established when the parties sign, seal or press their fingerprints. The tender documents belong to the offer in the contract, and these provisions are also applicable. However, if you pursue safety, try to personally sign and affix the official seal of the unit.