Bills can be accessed by
1. clicking on Bookings Module
2. clicking on Bills
All the bills are listed under the Bills module.
When client make a booking it creates an invoice. However, when an on site guest wants to add something to a booking there's an option to add to a new bill. This is helpful when client has already paid the default package but on site wants to book more items.
It is possible to Jump to alternative bill by clicking on the box under the booking number in the booking page.
Some businesses deal with multiple currencies and because one invoice cannot include two different currencies at the same time, the system always creates an alternative bill. Read more about paying in multiple currencies from here.