There are three types of plate boundaries: divergent boundaries where plates move apart, convergent boundaries where plates push together as they move towards each other, and transform boundaries where plates slide past one another in a sideways motion. Plates can move in different ways depending on the type of boundary, with divergent boundaries creating new crust as the plates spread apart, convergent boundaries resulting in one plate moving under the other in a process called subduction, and transform boundaries causing the plates to rub horizontally alongside one another.