I am programming a free body force diagram and as part of it a am allowing the user to adjust the angle of the plane and apply a force to an object on such plane at any angle to the horizontal. My question is, if they apply a large enough force horizontally while the slope is on an angle would the object lift from the plane? Any help/advice would be appreciated
Your force has a component along the slope, so yes, the object will move along the slope. It will not leave the surface though, if that's what you mean by "lift"
If you find it counterintuitive why the object has a vertical acceleration component despite your applied force being horizontal, you must think about the normal force. This is always, as the name suggests, normal to the surface i.e. the slope. Hence, it has that vertical component you seek.