How to Hide or View Your Mac’s Toolbar
Some windows on your Mac display a row of icons at the top of the window, known as a toolbar. While the toolbar gives you one-click access to commonly used commands, such as saving or printing a file, you may want to hide your Mac’s toolbar so that it doesn’t clutter up the appearance of a window.
To give you the option of hiding (or viewing) a window’s toolbar icons, a window might display a Toolbar button in its upper-right corner.
To toggle between hiding and displaying a toolbar, click the Toolbar button. Some programs may give you the option of hiding its toolbar another way, such as by choosing View→Hide Toolbar.
Not all windows have a Toolbar button.