Invoice total Field

I know this is basic, but I cannot figure out what procedure to use in the “Total” field for a series of line items. I have tried “Sum”, “Total” and may a few others. Just want to total up an invoice form. Thanks

See the documentation in the Panorama X Help: “Line Item Fields”:
To add up a series of line items you can use the sum( function.
(You need a calculating function, not a procedure statement.)

Thank you!!