Add the invoice number to the filename of the invoice. So, when, in the dialog window, the user types file123.xml, and the invoice number generator returns 32018, the final name will be 32018 - file123.xml.
Make this an opt-in/out in the user interface: in the invoice number section, add a checkbox if the invoice number is not yet set.
Add the invoice number to the filename of the invoice. So, when, in the dialog window, the user types
file123.xml, and the invoice number generator returns32018, the final name will be32018 - file123.xml.Make this an opt-in/out in the user interface: in the invoice number section, add a checkbox if the invoice number is not yet set.