@DavidOverholt it happens when the Sales Invoice Journal is updated. It is automatic. Again, that means it only works from SO Invoice Data Entry, not from Shipping Data Entry.
@WayneSchulz I work with a client that has decided to email invoices ""AFTER"" they have been updated to the permanent files; via Paperless. Instead of having to worry about sending invoices, then getting a Credit Card Decline, or forget to apply a deposit. AR --> Reports --> Invoice History Printing --> SO Invoices, Today's Date only. They have a Sub Report that prints on their Invoice that lists the Current Invoice Balance. And if the Balance is 0.00, then the words on top say RECEIPT, not Invoice.