Are you looking to prevent no shows for your appointments? You can set up a no show fee which will take an authorization for the card when the booking is made, and any amount can be charged later to the card as needed.
You can set this up under the "Set Up" page, select on "Service" and indicate "Price" option as a "No Show Fee":
***NOTE: The No Show Fee is only available for accounts that you have integrated with our online payment processor/s.****
You may also enable "require credit card", which allows you to require customers to enter their credit card information (during the booking process):