"Impeachment is the process by which a legislative body levels charges against a government official. Impeachment does not in itself remove the official definitively from office" (from Wiki)
So impeachment is simply a fancy word for "accusation".
But to the vast unwashed masses, OH MY GOD, TRUMP WAS IMPEACHED!!!!
ANYONE can "level charges" against ANYONE.
Me: "I think it was you who stole my lawnmower last summer!"
You: "I did not. You're wrong".