This is just an example of a custom link created using message text substitution syntax.
You would display a booking form on this page managed by some contact form plugin like Contact Form 7 or Gravity Forms. This would be a manual process and more convoluted than using Cab Grid’s built in booking form and customising it to your needs.
However, because you have created a dedicated page for this specific journey (in this case London to Heathrow), you would already know some details in order to populate the form – such as price and destinations.
Example:
Book London to Heathrow
Date:
Name:
Email:
Phone: