Question

What happens when resultant force acting on an object is non-zero?

Answer 1

then the object moves in the direction where the force is less acting

Answer 2

The object will start moving in the direction of net force.

But remember you may confuse as a beginner that a mass m lying on floor is exerting mg downward. But by Newton's third law floor is also exerting equal and opposite force that is what we called normal reaction so net force is zero, that's why it remains at rest.

Thanks