At a convergent boundary, two plates

At convergent plate boundary, two plates collide. There are two cases of convergent plate boundary:

Case 1: Oceanic plate collide against continental plate

In this case, the denser oceanic plate will subduct under the less dense continental plate.

An ocean trench will be formed at the place of subduction, while rocks at the continental plate would be folded up to form fold mountains or volcanoes.

Case 2: Continential plate collide against continental plate

As both plates are light,none will subduct and both sides of rock will be folded up to form fold mountian.

One example would be Eurasian Plate against Indo-Australian Plate collsion, forming the Himalayas.

Hope it helps!