To force a browser to download the contents of a link rather than display it, you can use dl=1 as a query parameter in your URL. For example:
https://www.dropbox.com/s/a1b2c3d4ef5gh6/example.docx?dl=1
Note: The original shared link URL may contain query string parameters already (for example, dl=0). App developers should be sure to properly parse the URL and add or modify parameters as needed. The links may also redirect to *.dropbox.com/s/dl