I am doing a booking form for course bookings and if the people haven't found out the available dates yet they need to go and look at the course calender held in Outlook.
How do I insert a hyperlink in the form so it stay clickable rather than appearing as text?
There's no "hyperlink" object that I'm aware of, but you can use a button to navigate to a web page using xfa.host.gotoURL. You can set its properties to remove the border and background and set the button's label to look like a link.