Tipping for Walmart grocery delivery

We have Walmart + which it states when you purchase Walmart + that it includes tipping the drive, and you don’t have to. Most of the time when I order groceries I pay for the fast delivery that cost 10 or 5 dollars extra am I supposed to leave a tip on top of that ? I don’t know how much they make and if they’re getting paid by Walmart or if they get paid by tips?