you can do SetOptions[EvaluationNotebook[], DockedCells :> {}] and there are options to remove the window frame, etc. but i think if you are using certain

you can do SetOptions[EvaluationNotebook[], DockedCells :> {}] and there are options to remove the window frame, etc. but i think if you are using certain licenses the toolbar may not disappear. and the main toolbar never disappears, to my dismay