I keep my own, locked up in a safe.
Who keeps all of our documents and information in the country/state?
The National Archives preserves government and historical documents and records in the United States.
That is a hard question to answer because there are many offices that hold documentation .. So it depends on what specific documentation you are referring to.
Most agencies keep their own. Social Security in the US, keeps theirs in a cave in Missouri. It naturally has the correct humidity to keep them preserved.