I was trying to make the items seem to float in the air, so I was going to use armor stands and then, I gave them the invisibility effect, but the problem was that the armor stands were following me with the items in their hands, and when it was over, the effect the armor stands returned to the place where I had placed it. Also if you save and quit and go back on the items grow huge.

If you want to do it just follow this steps:

1. In Creative mode put an armor stand on the floor with an item in hand.
2. Give it invisibility with this command: /effect @e[type=armor_stand] invisibility 20 1 true
3. Walk a few blocks.
4. Save the game and quit
5. Go back to the world