How is it possible to add all the force components to find resultant when forces are acting at different points on the body?
If the body is subjected to a force or forces that do not act on its CG then there will be torque which has to be countered by reaction forces acting as a couple at the supports with equal magnitude and opposite direction which equate to to torque create by the forces acting on the body.
By definition a static body means it is not accelerating or rotating:
$ \sum F_x=0, \sum F_y=0, \sum F_z=0 \ and \sum M=0$.
However if the forces are acting through CG of the body then we can just go ahead and add them up as vectors.