Definition: This is an action or thing that citizen is required to do by law.

I'm gonna go out on a limb here and say Mandatory duties

Explanation:

Mandatory Duties of U. S: U. S. citizens must comply with certain mandatory obligations, including: Obeying the law, Paying taxes. Every U. S. citizen must obey federal, state and local laws, and pay the penalties that can be incurred when a law is broken.