Drive Plug-in for Microsoft Office

The Drive plug-in for Microsoft Office allows users working in Word, Excel, PowerPoint, and Outlook to open documents directly from Google Drive, and save to Google Drive, without leaving their Office programs.
To use the Drive plug-in it must be installed on your computer. Download the Google Drive plug-in.

The following versions of Microsoft Office are supported:

Office 2010, 2013, and 2016 for Windows.
The following Microsoft Office programs are supported:
Word, Excel, PowerPoint, and Outlook. 
Google will not support Office for Mac:
Mac and Windows clients can also access or save their Office files through Google Drive File Stream. Please visit the previous link for further details on how to download. 

For more details please review:  Install the Drive Plug-in for Microsoft Office.