Sedimentary rocks are those that are produced by the deposition of sediments (small particles). The sediments cluster and are cemented that produces a rock. Sedimentary rocks are also called soft rocks as they are not produced by heat factor but are produced by the weathering of the rocks that are exposed on the Earth surface.
Metamorphic rocks are those which minerals are changed by heat not directly magma but heat which does not melt it but only changes the mineralization.
Igneous rocks are those which are produced by the direct melting rocks (magma). The magma cooling in the subsurface are called plutonic or intrusive rocks and those lava cooling on the surface are the volcanic or extrusive rocks.
The rock cycle changes the rocks from one form into another.