How do I get an invoice?
Edited
After a payment, only a receipt is available, find it under Billing → Billing history. If you need a proper invoice, request a top-up invoice from sales before you pay (available for amounts at or above ~1,000 EUR/USD). You can download past receipts individually from there too. To have receipts emailed somewhere specific, such as a finance inbox, add the addresses to the Recipients field under Billing → Billing notifications - it accepts several, comma-separated, and covers payment receipts alongside the other required billing notifications.