From Joomla! Documentation
How to Access
Navigate to the Private messages - inbox screen. Then click the Settings button in the toolbar.
The Private Messaging Configuration screen allows you to set parameters to control how Private Messaging works in your Joomla! web site.
- Lock Inbox. Whether or not to lock the Private Messaging inbox. If set to "Yes", no Private Messages can be sent. Default is "No."
- Mail me on new Message. Whether or not to send an e-mail to a User when a new Private Message is received. Default is "No."
- Auto Purge Messages. The number of days after which to delete Private Messages. Default is 7 days.
At the top right you will see the toolbar:
- Save. Save it and return to editing the menu details.
- Cancel. Go back to the main screen of the Manager, without saving the modifications you made.
- Help. Opens this Help Screen.