You can delete a message or ALL messages from your inbox and sent tab. Keep in mind that this won't delete them from your recipients inbox. It isn't possible to delete sent or received messages from a recipients inbox.
To Delete a Message:
1. Click on MESSAGES on the menu, you will auto-directed to your Inbox
2. On a per message basis click on the red trash can next to the message
To Delete in MASS quantities:
1. Follow step one from the above reference
2. Click on the filter icon
3. Select Filter needed
4. Delete desired messages
To Delete ALL messages:
1. Follow step one from the above reference
2. Click on Select All
3. Click DELETE
4. Complete confirmation by clicking Yes
