Hello
1. I want to customize the invoice VM Invoice generates, but cannot find a template for it. Where is it? Will it be overwritten with an upgrade?
You can edit this in administrator/components/com_vminvoice/helpers/invoicehtml.php
Yes, this file might be overwritten on upgrade
2. I need to change language to Norwegian, but even if I change every vminvoice Norwegian language file the language continues to be English. Where do I change the fieldnames in an invoice to Norwegian? Will it be overwritten by an upgrade?
The translation files need to be in language directory, as other Joomla translation files.
If you create your own translation file, it will NOT be overwritten on upgrade.