How to share a Dropbox file or and folder with someone who doesn't have a Dropbox account
Note: Until you share a file or folder with someone who has a Dropbox account, it will say “Only you” have access to that file or folder. So if you share a file or folder with someone who doesn’t have a Dropbox account, it will still say “Only you” have access.
How to share a file or folder with someone outside Dropbox
You can send a shared link by email, Facebook, Twitter, instant message, social networks, wherever you want.
Dropbox Professional, Standard, Advanced, and Enterprise customers can also add passwords and expirations to shared links.
How to stop sharing a file or folder with someone outside Dropbox
You can delete the link to immediately stop the person you have shared it with from accessing that file or folder. Learn how to remove a link to a Dropbox file or folder.