A new feature in Pokémon Sun & Moon is the inclusion of Battle Styles. This allows for you to change the image of your trainer as you enter a battle, as well as the manner in which they throw the Poké Balls. There are eight different Battle Styles and they can all be changed at will by speaking to an old man in Malie City's Outer Cape
The eight styles are unlocked through various different means such as defeating certain trainers or even getting through various challenges.
Battle Style List