How do I make my pet pick up items?

When I started the game, I’m sure I saw a tutorial tip that I could have my pet pickup items directly into their inventory, but I cannot remember how to do that.

How do I click an item on the floor to have my pet pick it up? Right now, I am picking up the junk and then have to move it from my inventory to that of my pet and I’m just too lazy for that. 🙂