They are three different types of plates: separating, colliding and sliding plates.
Separating plates: as two plates separate, magma wells up to fill the space in between them. The magma cools and becomes solid, which forms a new crust. Volcanic islands, volcanic mountains and mid-ocean ridges form wherever plates separate.
Colliding plates: when plates collide, the crust is destroyed. When an oceanic plate collides with a continental plate, the heavier oceanic plate is forced under the lighter continental plate and down into the hot mantle below, causing part of the oceanic plate to melt and part of the continental plate to buckle. These processes form fold mountains and volcanic mountains.
Sliding plates: as two plates slide past each other, their edges sometimes become locked together. As pressure builds up, the edge of one plate may snap or suddenly jolt forward. Great waves of energy are then released, causing the earth to tremble in the form of earthquakes.