Each one has a different purpose of using MS Word, for example i use it for Macros. In MS Office 2007 and above versions we can add shortcuts & Quick access buttons as per our requirement.
‘Quick Access panel’ enables us to add shortcuts in MS Word.
This panel is on Top Left side of the MS Word.
Save, Undo, Redo options are enabled by default, you can add the remaining as per your requirement (like Quick Print, Print Preview Etc).
For more options you can customize the panel. To customize open 'More Commands…'
Select ‘All Commands’ from ‘Choose Commands option’ (or else you can choose the option as per your requirement.
Select the option from the list and click Add and OK.
If you don't want the shortcut on MS office just right click on it and select 'Remove from Quick Access Toolbar'