If you want to sign a photo contract, you need to make an electronic signature first. After making electronic signature, users can upload contract documents such as PDF, Word and PNG or use online templates to generate contracts, and then add electronic signature. In order to verify that the electronic signature is exclusive to the user, the security signature ensures that the signature behavior is controlled by the signer by reserving the random dynamic password of the mobile phone number, that is, "true will". First of all, we must distinguish what kind of contract it is; Both parties have reached an agreement on the terms of the contract and signed and sealed the contract documents, which can be regarded as having accepted the constraints of the contract contents; Generally, both parties sign and seal the contract; Due to the different types of contracts, the establishment of a contract does not mean that the contract will definitely take effect.