The signing of a contract between companies requires the signature of a legal person. Specifically, civil and commercial contracts between companies require both the official seal of the company and the signature of the corresponding legal representative. According to the law, when a company signs a contract, it is usually signed by the legal representative on behalf of the company, so it needs the legal representative to sign and affix the official seal. Therefore, if a contract is signed between companies, in order to ensure the validity of the contract, the legal representative needs to sign it.