What are the meaning of cam shaft and crank shaft and mention applications of that shafts?

In terms of a piston engine;

Crank shaft is actually a part of the engine itself. This is what receives the power in form of torque from the reaction in the cylinder and outputs it to the clutch -> gearbox -> wheels

Cam shaft receives power from crank shaft to operate the valves of the cylinder.

(That motion however can be designed differently (Overhead direct acting cam shaft vs Pushrod operated)