The Quick Access toolbar is a small, customizable toolbar to which frequently-used commands may be added.
To customize it, click the down-pointing arrow and this menu is displayed:
Choose More Commands and this sheet is displayed. Click the first dropdown menu and choose the command category -- in this example, the command we want is Save as PDF, which is in the File category:
Choose Save as PDF and click Add, then click OK. The Save as PDF icon will be added to the Quick Access Toolbar:
Adjust the order of icons in the toolbar by moving one or more up or down via the Up / Down arrows on the right of the window.
To remove all additional icons from the Quick Access Toolbar and return it to the default set, click Reset. Additional icons can be added again, if desired.
The Quick Access Toolbar may be displayed below the Ribbon instead of above it. Check that box to reposition it.
To change a keyboard shortcut combination, click Customize and the Keyboard Customization dialogue will appear.
To learn more about the Quick Access Toolbar watch the following video: