Between each tectonic plate, there are boundaries. All the tectonic plates are always moving towards, against, and away from each other. There are three possibilities when these boundaries collide, convergent boundaries, divergent boundaries, and transform boundaries.
Convergent boundaries occur where two plates are pushing against each other forming mountains. One example of this is the boundary between the Eurasian Plate and the Indian Plate in the Himalayas
A divergent boundary is where two plates move away from each other forming a gap. One example of this is the boundary between the African Plate and the Arabian Plate in the Red Sea.
A transform boundary is where two plates slide past each other. One example of this is the boundary between the Pacific Plate and the Australian Plate, crossing New Zealand.