By default, whenever a service is booked, it requires your client to enter their credit card information. 

This works in conjunction with your cancellation policy to ensure that your client is charged a cancellation fee when they cancel or reschedule their appointment.

Should you wish to allow your client to book without having their credit card information captured, you can do so by turning on the Disable Card Capture For This Service option when you create or edit a service.

When this is toggled on, AR will not ask for credit card information when a client is booking this service online.