Collect payment for billable order positions already present in procedure state.
Prerequisites (implicit): Positions from Add Position (AddPositionToOrder), Order from menu (OrderFromMenu), Add Nights Position (AddNightsToOrder), or stashed reorder positions. Completes immediately when the gross total is zero.
Configuration highlights: Payment provider, invoice template, optional fiscalization, allow-waiting-payment.
Typical place in the funnel: After pricing (and usually contact/address); almost always followed by sync + notify.
Downstream (very stable in live data): Create a reservation (SyncReservationEntry) and/or Create an order (SyncOrderEntry) → Create an invoice (SyncInvoiceEntry) → Inform guests via email (InformGuestViaEmail) → Inform operators (InformOperator), sometimes Reorder menu (ReOrderMenu) or a closing Block Procedure (TextBlocker).
See patterns booking-with-payment, booking-classic-occupancy, and booking-menu-checkout.