The contract is valid only if it is signed with a blue pen, because the color of the pen is not an important factor to determine whether the contract has legal effect. The important elements of the validity of a contract are: the actor has corresponding civil capacity; Meaning is truth; The contents of the contract do not violate the mandatory provisions of laws and administrative regulations, and do not violate public order and good customs.

Legal objectivity:

civil law

Article 490

If the parties enter into a contract in the form of a contract, the contract shall be established when the parties sign, seal or press their fingerprints. 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.