suppose an object of mass M is raised to a height h above the ground what is the amount of work done what happens to the object potential energy in the process

Solution,
To raise an object of mass M up to a certain height h, work need to be done on it against the gravitational pull (Mg).
Work done, $Work done \left(W\right)=Force \left(F\right)\times displacement \left(h\right)$
Here, the force applied should be atleast F=Mg to displace it vertically by a height h. Hence, the work done is given by:
$W=Mg\times h=Mgh$
This work done on the object is stored as the potential energy of the system. Hence, the potential energy of the body will be raised by an amount, Mgh.