1. Attachments in the contract need to be signed separately.

2. Legal provisions: Civil Code of People's Republic of China (PRC).

Article 490 Where the parties conclude a contract in the form of a contract, the contract is formed when the parties sign, seal or fingerprint it. Before signing, sealing or fingerprinting, one party has fulfilled its main obligations, and the contract is established when the other party accepts it. A contract shall be concluded in written form as stipulated by laws, administrative regulations or agreed by the parties. If the parties do not do this in writing, but one party has fulfilled its main obligations and the other party accepts it, the contract is established.

Second, what are the effects of the contract?

The validity of a contract means that the parties to the contract must perform their contractual obligations and may not change or cancel the legally binding force of the contract without authorization, that is, the legal effect.

1, valid contract.

The so-called valid contract refers to a contract established in accordance with the law and legally binding between the parties. Judging from the existing legal provisions, there is no unified contract entry into force conditions. However, from some provisions of existing laws, we can still draw the conclusion that an effective contract should have the same characteristics.

2. Invalid contract.

"Invalid contract" is relative to a valid contract, which refers to the situation that although a contract is established, it is confirmed to be invalid due to violation of laws, administrative regulations or social public interests. It can be inferred that its main characteristics are: illegality; The unenforceability of invalid contracts; Invalid contract is invalid from the beginning; An invalid contract is naturally invalid, and can be actively examined by a court or an arbitration institution without the claims of the parties. It also points out that invalid contracts should not belong to the category of contracts because they are not legally binding.

3. Contracts with undetermined validity.

The so-called contract with undetermined validity means that although the contract has been established, its validity has not been determined because it does not fully meet the relevant legal requirements for entry into force. Generally speaking, it can't take effect until the right holder expresses recognition or approval. It mainly includes three situations: "First, a contract that cannot be independently concluded by a person with no capacity or with limited capacity according to law must be approved by his legal representative before it can take effect;" Second, the contract concluded by the unauthorized agent in my name must be ratified by me before it can be legally binding on me; Third, a contract concluded by a person who has no right to dispose of the property rights of others is invalid without ratification by the obligee. "

4. Cancellable contracts.

A revocable contract refers to a contract that can be revoked according to law because the parties made a wrong expression of will because of untrue or serious misunderstanding in the process of concluding the contract.

The above is the content compiled by Bian Xiao. We can understand that according to the regulations, the annexes in the contract need to be signed separately, which is binding on both parties and is also one of the purposes for both parties to sign the contract. There are relevant provisions in the law. If you have any questions, you can consult relevant lawyers.