Quick access toolbar
 
The quick access toolbar is located by default at the top of the Word window and provides quick access to tools that you use frequently.
 
The format of the name displayed in the title bar is 'Document Name - Microsoft Word'.
By default, only three commands appear on the quick access toolbar: Save, Undo, and Redo.
1
Place your mouse cursor over Save, Undo, and Redo.  
You can add more commands in quick access toolbar by clicking on the quick access toolbar.
2

Click on the quick access toolbar and you will see commands available, which you can add on quick access toolbar.