I have seen these two words and found they mean the same. Could someone explain the difference in usage?
I mean their meaning is quite similar, as both refer to something that is left, leftovers from something, a rest, something that remains. Technically übrig would be a part of a bigger collective that remains or is surplus or not needed or whatnot, while verbleiben (bleiben = staying or staying the same) is more about the remaining then. But due to their shared word cloud of association you can probably use them synonymous in many cases. Though "verbleiben" is a bit more old-fashioned and formal. Like verbleiben could be used when you're running out of something like "Ich möchte die verbleibenden Stunden im Kreise meiner Angehörigen verbringen" (I want to spend my remaining (final) hours with my family" while übrig is more like "Ich hab etwas gebaut und die Teile waren über (übrig)" (I build something and those parts where surplus).
Or official empty phrases like "ich verbleibe mit freundlichen Grüßen" (yours sincerely/truly) would use verbleiben and not übrig. But yeah in most cases the meaning is so similar that you can find a formulation for one or the other.
Edit: That is of course assuming that you're talking about the semantics of word.