What kind of rock are you most likely to find fossils in?
Sedimentary rock has the most fossils. Recall that sedimentary rock is created as layers of sediment pile on one another and are compressed together. Organisms can get caught between the layers when they die and become fossilized.
Igneous rocks are formed from drying magma. The heat from that would destroy any organic material.
Metamorphic rocks may also contain fossils, however there is a good chance that organic material may be destroyed from the forces that the earth exerts on the rock including heat and pressure.