How can I Add message to Booking form?

Hello, How can I Add message to Booking form please? We have customers paying for Tours before checking small details. Just want to add a short message to the booking form to Use “Send Enquiry Form First” before Paying for Tours. Can you please show me where to add?

ALSO: On Send Enquiry Form, How can I add Origin URL to the form. So when people Send an Enquiry it shows the page URL that they sent the Enquiry from.

Love the Theme, thanks for your help so far