I will give you the situation this came up in, but essentially I would like to know whether moving away from a prone creature would trigger an opportunity attack or not.
If you move 20 feet to attack as a Warhorse while in druid Wild Shape, the creature needs to do a DC 14 Strength check or be knocked prone. (PHB p.311)
If the target fails and is knocked prone you can make a bounus attack with your hooves.
If you want to move away to be able to charge again on your next turn, would this normally trigger an opportunity attack?
I am not sure because the creature would have the prone condition, so guidance with this would be helpful.