When all users are done with a message and there is no need to hold it the Inbox, you can click the Archive button above the message body to archive the message.
You can view the archive by clicking the inbox (on the left side of the screen), and choosing Archive.
Please Note: Messages that have been archived on the server are inaccessible to mobile users. Mobile devices have a smaller, personal archive folder that is separate from the server and For HIPAA compliance, will be purged at some point (the default is one week)
You can restore messages to the inbox by choosing Unarchive
Please Note: Unarchiving a message may not make it become available to mobile users if they haven't already downloaded it.