How to use the Upfront Billing option in group events
For group file event attendees who wish to pre pay for their session, use the Upfront Billing option located on the Group File Event Attendee page.
Select the Attendee for whom you need to create an invoice for and click on Upfront Billing.
This will create a draft invoice for a future event without the need to mark attendance.
You can then process this invoice as per the normal process.