A basic invoice layout is included with Kartris. If you are printing onto headed paper, this version may well suffice.

However, if you need to customize this, you first need to understand the files involved in generating the invoice.

Invoices can be viewed from two places; in the back end (by store admins) and also by customers within the 'My account' section. The back end invoice always uses the Invoice.master template in the Admin skin. The front end invoice display uses an Invoice.master if one is present in the selected front end skin. Otherwise, it defaults to the Invoice.master in the Admin skin. These master pages are the place you need to edit if you wish to add header and footers to the invoice(s), or company logos.

If you need to edit the HTML layout of the invoice itself, for both cases, this uses the following file:

UserControls/General/Invoice.ascx

This is the place to edit if you need to add your VAT number or any other extra fields that will appear on every invoice.