Hi Suwanee,
Last year, we welcomed Mailbox to the Dropbox family: the light, fast and easy email client that makes managing your email a breeze.
Download Mailbox
Available on iOS, Android and Mac OS X desktop
As a thank you for trying it, we'll even give you 1 GB of free Dropbox space. After downloading Mailbox, sign in with your Dropbox account or go to Settings and add your Dropbox credentials. The free space will be added to your Dropbox account automatically within 24 hours.