[donavichi]

In your X-Cart Admin, go to General Settings > User profiles options and scroll to the bottom of the page - here you can add extra fields and choose what type of field they should be and where they should go, according to your needs.

These will then show up on your order invoices (when they are ticked on the user profiles options page), although this might not suit all of the things you're attempting here.

Alternatively, you can edit skin1 > mail > HTML > order_invoice.tpl and duplicate the 'customer name', 'address' and 'order number' elsewhere on the page.

Can't think of any other ways off 'top of my head

If you want more help you should probably try to post in the right part of the forums in future - the 'member websites' section is not the place to be asking on help in 'modifying templates', there's a ready-made area just for that elsewhere in the forum...