Related Questions:
Add an additional fee to my invoices
Procedure:
Event Temple does not have a surcharge function, perse. However, it is possible to add invoice items that would simulate the charge.
Access the Invoice that requires a surcharge
Click the Add Items button at the bottom of the invoice
Input a value in to the Name field
Input a price for your surcharge
Click Save at the bottom of the screen
Additional Information:
If you use Surcharges regularly, you can create a menu item that can be added from your menus in order to track the surcharges that have been added to invoices.