I just want to save my Word and Excel files into my Dropbox account. I'm using Windows 8.1 and Office 365.
If you use DropBox, Box, Google Drive, Tresors, Copy, or any of the oodles of online file storage services, you can save documents directly to the service provided you have a sync utility installed for the service. (Those services all provide sync utilities.)
You can even set different services for each Office application, if you wanted to.
Browsing to that folder can take more steps than you might like.
When you click the Save icon on the Quick Access Toolbar, the a file explorer window opens. Save your file and it will sync up to the server after you close the Office application.