dnd 5e – What Should I Give Level 20 Players

I really like giving out loot and spells but what should I give to level 20 players. It would be also really nice if someone should tell me what to give to low level players as well. I do own a copy of the DM’s handbook (and it tells me what to give) but should I give the less, more or the right amount. I’m asking about 5 edition dungeons and dragons.