Full Slate offers 'credit card capture' so you can collect credit card information when clients schedule appointments to charge their cards if they do not show for their appointment. When a client enters a credit card number, we pass it straight to the payment processor for safekeeping. Full Slate never stores or exposes the full card number.
To keep credit cards on file, you need an account with a payment processor that supports saving cardholder information and charging customers after the fact. Stripe provides this at no cost, and Authorize.net has an add-on called Customer Information Manager (CIM). These payment processors enable you to charge a card on file without actually seeing the number itself.
To set up 'credit card capture', go to Setup > Client Payments. Then select your processing gateway -- either Stripe or Authorize.net CIM -- and enter your account information. Choose what information you want to display and collect and save your changes. Please note that a service will need to have a price (as established under Setup > Services) in order for credit card information to be captured; otherwise, the system assumes the service is free. Then for the question, "When required, what should clients be charged at time of booking?" Choose, "Nothing, just keep card on file".
If you intend to charge for missed appointments, be sure to disclose your cancellation policy to clients when they give you their card. We suggest using the “policy” box for this purpose. This can help reduce the chance of charge-backs or losing a dispute (not to mention a client). What we refer to as the policy box is located under Setup > Client Payments.