Why getting domaina / wp-travel-checkout/

Please advise, why we are getting https://drisshyaholidays.com/wp-travel-checkout/

This is when we are checking the availability.

Also, how can we change the button name (check availability) & Confirm Booking.

And, how can we add the contact no. of guest in billing details.

The page I need help with: [log in to see the link]