Hi,
It seems like you're looking for LibreOffice Macros to automate the task of creating invoices. Can you explain the following:
1. From which format will the Data be sourced to Fill the Forms? A spreadsheet file or some Database?
2. What do you mean by a Setup Page? Is it some sort of UI (User Interface) with buttons in LO to start the automatic functions?
This is an interesting job, and LibreOffice is a good free office tool to incorporate in your business. Looking forward to your reply.
Regards,
Hisham