Players use their equipment to interact with the digital world.
Interaction virtual space in a location-based mobile games may happen implicitly. For example, the movement of a player in the real world may trigger events that change the state of the game.
More straightforward is the explicit interaction by operating the game equipment, e.g. players may interact through a smartphone screen.
A common caveat is to avoid too much interaction with a device screen, and promote interaction in the the real world.