Effective. Only signing a contract is as effective as pressing a handprint or seal. Generally speaking, if a contract is not legally invalid and does not violate the autonomy of the parties, it will generally take effect from the date when the contract is established. Just signing does not affect the validity of the contract, so it is valid. An agreement is a contract with economic or other relations signed by a country, a government, an enterprise, a public institution, a group or an individual after full consultation on a specific issue.