Konstantin1
You must first create a Custom List by going to Admin Panel > Manage > Lists. Once the list has been created you can add it to any Form by going to Admin Panel > Manage > Forms. If you want the list on every Ticket and would like it to be exportable you would need to add the field to the Ticket Details Form. If you don't want it on every Ticket or if you don't need the data to be exportable then you can add it to a Custom Form. Just keep in mind that if you add it to a Custom Form you must ensure you attach the Custom Form to a Help Topic. This way when an Agent/User selects the specific Help Topic the list will appear.
Cheers.
