Can balance force change the shape of object

and how? And can unbalance force can change the shape of object and how?

Yes, it can change it's shape because body changes it's shape because of stress on it which depends upon pressure and pressure is a scalar quantity, so it adds up to stress irrespective of the direction of force.

In case of net force zero, pressure on the body will add up to apply more stress which will change it's shape.