What do you put on the bottom of a budgie cage?

There’s a lot of things you should not put in the bottom of a cage, so we’re just gonna go to the single thing you need, Paper, just reqular ole printer paper. Line the bottom of the cage with paper and change it out everyday or two. Paper is also something like like to chew on, so don’t have it stick up from the bottom or they will pull it right up. (Which is SUPER fun to watch btw)