The checkout shortcode and a few others display system elements. These elements do not appear within the Elementor interface, because they cannot be edited with a page builder.
Try adding the checkout shortcode ( [mphb_checkout] ) through the Shortcode element of Elementor.
If you are still having any issue with the shortcodes, please, submit a ticket for our support team here.
Do you mean you can not see anything on booking confirmation page when you are redirected there after you click confirm reservation button on search page or while checking availability of accommodation? Or you mean you simply visit the page and it is just blank?
Make sure there is added [mphb_checkout] shortcode on your booking confirmation page and make sure this page is selected at Hotel Booking settings. Also make you passed all the steps of reservation before you were brought to booking confirmation page.