Audit Trail is a set of destination and source records that tracks the actions performed on every email message that passes through Email Security. All activity performed by users are logged, where the Global Administrator can view and search these activities.
Here's how to enable Audit Trail:
Go to Investigate | Tools | Audit Trail
Click the Settings button.
On the pop-up window that displays, click the On or Off button to Enable Audit Trail. This enables auditing for both inbound and outbound email messages.
Specify how long to Keep auditing files for with the drop-down list. You can select between 1 day to 7 years.
Click Apply when finished.
How to export file:
Click the Export to CSV button to export a list of Messages Found. The list is downloaded to your local system.