Formation of igneous rocks due to hardening magma

When magma reaches the surface it is then called lava and the eruptions of lava and ash produce volcanoes. The lava that reaches the Earth's surface will harden and become igneous rock. ... These are called intrusive igneous rocks because the magma has intruded into pre-exiting rock layers.

When two tectonic plates collide and one or both push upwards they also push up the crust,a mountain will for so that will be your answer. hoped this