From Bulbapedia, the community-driven Pokémon encyclopedia.
A Pokémon Stylist (Japanese: ポケモンスタイリスト Pokémon Stylist), also known as a Poké Stylist, is an anime-exclusive type of a Pokémon user. Their role is similar to a fashion designer's in that they design outfits for people. They also design different accessories for Pokémon.
Pokémon Stylists were featured for the first time in Arriving in Style!, with the debuts of Paris, Cocoa and Hermione.
Lila, who appeared in Battling the Generation Gap!, was also shown to be a Stylist.