Legal analysis: The key is that what is added before you sign is valid, and what is added without your knowledge after you sign is invalid. There should not be a whole line of blanks in the middle of the contract. If there are a lot of blanks at the end of the contract, you can mark the following blanks after the last line of valid text: If the following blanks are a fixed-format contract and a handwritten blank is reserved in the middle, then when it is determined that it does not need to be filled in, Cross out.

Legal basis: Article 490 of the "People's Republic of China and Civil Code" Where the parties conclude a contract in the form of a contract, the contract is 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 or the parties agree that a contract should be concluded in writing. If the parties do not use writing but one party has performed its main obligations and the other party accepts it, the contract is established.