Noa works as a waitress at a restaurant in Hau'oli City and just so happens to be the reigning champion of the Pokémon Pancake Race. She's the one who clued Ash in on how the whole thing works when he and Professor Kukui stopped by her place. She and her Alolan Raichu spent time training alongside Ash and Pikachu leading up to the event.
When race day came around, Noa and Raichu were looking solid—Raichu had the lead going into the final stretch. But then Team Rocket and Bewear showed up and caused enough of a mess to distract them at exactly the wrong moment. Samson Oak's Komala took advantage and crossed the finish line first, bumping Noa down to second place, tied with Ash. She didn't seem bothered by the loss though, telling Raichu they'd come back stronger next year.
Content compiled by AnimeList.moe from publicly available sources.