This feature allows you to save incoming, outgoing, and mailing list messages for a specified amount of time. The system stores the messages in the mail directory in the user’s home directory. This means that it is still stored with in your cPanel so keep that in mind since it may affect your over all disk space availability. This is just another option for you to save your emails.
To access this feature you will need to log into your cPanel and scroll down to the "Email" section and click on the "Archive" icon.
The screen shot below shows an example of the page that loads up. It will display all the domains that are added to your cPanel.
You have a two options to set up the Archive system. The first is to enable it for all of the domains under your cPanel and it allows you to select the amount of time you want to archive the emails.
The second option is to enable it for specific a specific domain. This also allows you to select how long you want the emails to be archived. You also have the option to download the archive email from here by clicking on the "Download Archive" link.