The Edit Booking page allows you to view information about the booking in various tabs. It also offers you a few icons that will link to pages that allow you to perform certain tasks.
As the system processes the booking, it will often add notes to the View Notes tab to say if a discount was applied during the booking, whether or not a coupon code was used, that sort of thing.

Amend booking. You will be taken to a special booking form where you can edit the booking, set a different grand total and change the deposit.

or

If a guest isn't booked in, you'll be able to book them in from here, or book them out if they're already booked in.

Here you can mark the deposit as paid. Useful if you want to take the cash at reception instead of over the internet.

You can add extra services to the customer's booking and invoice, using this link.

A printable confirmation letter will open as a popup.

Like the printable confirmation letter, but it will instead email the letter to the customer.

You may also see an invoice icon, in which case you will be able to view the guest's invoice when you click on this link. This is the same invoice that logged in, registered guests can see when they view their bookings (users can make bookings when they are not logged in, but they will not be able to see the details later on).

You can add a note to the booking using this icon.