How do I download (save) my su.webmail to use in a different mail client?

To download all messages in a folder in a single file (mbox format)

1. Open Webmail and login
2. Click the 'Folders' button
3.Select the folder you wish to download (i.e. inbox)
4. Choose Action: ''Download''
5. Save this file to your personal computer or flash drive.
 
This file will be in mbox format; which is the most common format for storage of mail messages.
An mbox is a single file containing all your messages mail messages.