Originally Posted by Lowengard As far as I know (30+ years of invoicing clients) there are no absolute requirements for an invoice in the US. As long as it includes ... you should be okay.

That is nice. Do I understand correctly that the invoice attached to this thread is OK as it is? Additionally I may remove the bank account information, right? But instead I should add the cheque after the cut-line. Is this cheque valid only when made on a specific paper-form or I can print it with any printer?

I also want to correct a misunderstanding - I'm not going to make invoices from Germany to US. I want to make Rechnung+ system usable in US by US freelancers or small teams to invoice US clients.