Depending on the situation:

1. If the two parties make the correction after clear consultation, even if the correction is made by handwriting, it will be valid.

2. If the correction is made by handwriting without consultation with the other party, the altered content will be invalid.

When modifying the contract, you need to pay attention to the following aspects:

1. Both parties to the main contract need to sign.

2. Both parties need to reach consensus on the modification matters.

3. If the contract is re-signed, the content of the original contract remains unchanged. You just need to correct the clauses that need to be modified and directly quote them into the new contract.

4. If you sign a supplementary agreement, you need to clarify the content of the main contract in the supplemental agreement, or make the main contract an attachment.

5. Both parties sign for confirmation and fill in the date.

Legal basis:

"People's Republic of China and Civil Code"

Article 490

The parties adopt a contract If a contract is concluded in writing, the contract is established when both parties sign, seal or fingerprint it. 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.