WindowToolbars is an option for Notebook which specifies the toolbars to include at the top of the window used to display the notebook on the screen.
WindowToolbars gives a list of toolbars to include. Typical possible elements are:
The detailed appearance and operation of toolbars differ from one computer system to another.
Toolbars are always shown inside the main frame of the window.
See The Mathematica Book: Section 2.10.2 and Section 2.10.13.
See also: WindowElements, WindowFrame.