What happens when two plates carrying continental crust collide?

These two plates will form mountains.

Explanation:

This is an example of convergent boundaries. Convergent Boundaries are formed when two plates move towards each other. Converge means to come together from different directions and meet at one place

In the case of you question, India and Asia are an example of a Convergent Boundary. According to the theory of Continental Drift - India crashed into India. The two land masses buckled and folded - forming the Himalayas!