Since the Alola region, Pokemon has slowly moved away from Hidden Machines (HMs) and replaced them with a new feature called Ride Pokemon. At some point in each Pokemon game, players are given a Key Item that allows them to ride on Pokemon that can fly, surf, or move boulders. Pokemon Legends: Arceus doesn't have a Ride Pager or a Rotom Bike, but it does have the Celestial Flute. The flute functions the same as the Ride Pager in Sun/Moon & Ultra Sun/Ultra Moon, and the Ride Pokemon essentially serve as "HMs" in the overworld.