It sounds like you would like to "get an invoice" from us or from a user in your nation? I am a little unclear on what exactly it is that you need help with!
I sent you an email to cover this with you directly, but if you would like to add a comment on this post for more details please do so.
Additionally, if any other folks have any questions regarding their invoices, feel free to send an email to firstname.lastname@example.org
Complete and current information on how to use NationBuilder is available in the documentation section.