Pivot Points setting in Maya

Every model (or transform node) can have only one pivot point. This pivot point is where the object rotates or scales on. The pivot point position doesn't affect the move tool.

Editing Pivot Points

You can easily edite this....
Create a cube. Scale it (r on your keyboard) to a rectangle so it's easier to see the effects of the pivot point's location.

Go to the rotate tool (e on your keyboard) and rotate the cube. Get a feel for how the rotate tool works with the pivot point in the center. After that, undo your rotations.
Go to the move tool (w on your keyboard), and hit insert on your keyboard.

Now, press 'd' on your keyboard and drag pivot ,and you can change the model's pivot point. Move it to one of the edges.

Now hit insert again to exit moving the pivot point and go back to the move tool. Now go to the rotate tool and rotate it.

Now it pivots on the right side instead of the center. It will pivot on wherever you put the pivot point. This also goes for scaling.
If you need to center your pivot point in your model, go to modify > center pivot.