The two forces that typically act on a mass on an incline are the weight of the object and the force exerted by the incline to support, or partially support, the object.

The weight and the normal force acting on the mass can be broken into their components parallel and perpendicular to the incline.  These components can be added in each of the two mutually perpendicular directions to obtain the single force equivalent to these two forces.  This resultant vector is directed down the incline.

In a typical situation there is also a frictional force acting in the direction opposite to the resultant of the other forces.  The net force on the object is the vector sum of the frictional force and the resultant of the weight and normal force.

We can in fact say that the net force is the resultant of all the forces acting on the object, in this case the weight, the normal force and the frictional force.

*& parachute