If you’re browsing your Dropbox account at their web site, select a document then look at the Open menu for options.
Copy to Paper – Paper is Dropbox’s own online collaboration tool.
Open in Word 2016 – the Dropbox site has detected the presence of Office 2016 on the computer.
Microsoft Word Online – opens the document in Microsoft’s browser based version of Office.
Show in File Explorer – this appears if the document is synced with your computer.