Where do you get married if you are Atheist or Agnostic?

I’m an agnostic, and do not believe in the bible. I also don’t attend church. When I decide to get married, and still want to have a wedding with my family where do I go to get married? Do I only need a legal paper to say I am “married” or do I need a priest? I want to be married but do not want the church involved, because I simply do not practice religion.