How to email attachment with invoice that does not have attachment listed first receipt to client

Hi Admin23 

To my understanding, the attached files will also be included first then the PDF copy of the invoice. There is no way in the software to re-order those so that the invoice comes first.

In saying that, I was able to achieve what you are after by downloading the PDF copy of the invoice, deleting it from the email, adding the desired attachment and then re-uploading the invoice to that email. While it is a long-winded way of doing it, that process does appear to have worked as intended for me and would achieve what you are after i.e. invoice then attachment.