Go to the "Νew order" tab, and right-click on the event you want to export its barcodes. In the window that appears, select "settings".

On the Event's settings page, in the "Εxport barcodes" field, press "export" (txt or csv).

If you do this procedure to scan offline your event's tickets, you do not need to import the file to your device. This process activates the process of updating your device with the barcodes of the specific event.

See more here.

Barcodes can be exported by a user with administrator rights.