Do you have any toolbars at all?

If you can't see any of your toolbars, you might be in full screen mode. Try the F11 key to switch between regular and full screen modes.

If you need to turn individual toolbars on and off, right-click a blank area of the tab bar to chose the ones you want to enable, or tap the Alt key to display the full menu bar and use View > Toolbars.

If you are showing the main toolbar with the URL and search box, you can add the print icon. Right-click an existing icon and choose Customize, then drag the print icon to the desired location.

Does that help?

Oh, and you can press Ctrl+p (or on Mac Cmd+p) to print any window, even if the menus and toolbars are not visible.

The print button isn't shown by default, you need to drag it to where you want it while in the Customize mode.

https://support.mozilla.org/en-US/kb/customize-firefox-controls-buttons-and-toolbars