Collect payment for billable order positions already present in procedure state.
Prerequisites (implicit): Positions from AddPositionToOrder, OrderFromMenu, 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): SyncReservationEntry and/or SyncOrderEntry → SyncInvoiceEntry → InformGuestViaEmail → InformOperator, sometimes ReOrderMenu or a closing TextBlocker.
See patterns booking-with-payment, booking-classic-occupancy, and booking-menu-checkout.