A contract refers to an agreement reached by date, place, content, form and signature or seal. Black handprint is not one of the ways to sign the contract, so this form of contract cannot take effect.

In order to ensure the validity of the contract, the following are the elements and conditions that the contract must meet:

1. The contents and terms of the contract must comply with laws and regulations and the public interest, and shall not violate the mandatory provisions of laws and regulations or affect the public interest. In addition, the content of the contract should be specific and clear, not vague or vague.

2. The parties to a contract shall be natural persons, legal persons or other organizations with full capacity for civil conduct. Before signing the contract, their respective rights and obligations should be agreed by exchanging opinions or other means.

3. The contract must be in written form, including written paper, electronic text and other forms, as well as ways to reach an agreement such as signing the contract and stamping. In the contract using electronic text, electronic protocol and digital signature can be used to ensure the authenticity and legality of the contract.

4, the performance of the contract must comply with the provisions of laws and regulations and the terms of the contract, and shall not be unilaterally breached. For the defaulting party, it shall bear the liability for breach of contract and make corresponding compensation.

5. Mandatory provisions must comply with laws and regulations, and shall not harm the legitimate rights and interests of vulnerable groups such as workers and consumers.

6. The conclusion and performance of the contract must meet the requirements of law, public order and good customs. You can't use fraud, coercion, using special status and other means to reach a contract, and you can't use the contract to make illegal profits.

To sum up, in order to ensure the validity of the contract, both parties to the contract should strictly abide by the relevant requirements of laws and regulations, adopt a written form, and sign or seal the contract. If both parties only need to use handprints, they can consider attaching photos or scanned handprints to the contract, and signing or stamping the pages attached with handprints.

Legal basis:

Article 143 of the Civil Code of People's Republic of China (PRC)

A civil juristic act that meets the following conditions is valid:

(1) The actor has corresponding capacity for civil conduct;

(2) the meaning is true;

(three) does not violate the mandatory provisions of laws and administrative regulations, and does not violate public order and good customs.