How does a convergent boundary form?
A convergent boundary forms when two tectonic plates which are expanding met.
In the mid Atlantic ridges new crust is formed. The new crust moves away from the ridge in both directions causing those tectonic plates to expand and move apart.
The earth is not expanding so the expanding plates will meet forming a convergent boundary.
Off the coast of South America parts of the Pacific plate collide (converge) with the South American plate. The Ocean plate is pushed under the continental plate, forming a subduction zone.
This is one type of a convergent boundary.
Off the coast of California parts of the Pacific plate collide (converge) with the North American plate. The two plates push against each other mainly side by side creating a transverse fault.
This convergent boundary is responsible for the famous San Andreas fault
The continental plate containing India collided with the continental plate of Asia. When two continental plates collide (converge) mountains are formed.
So when plates meet convergent boundaries are formed.