If you use a payment gateway that offers the feature to collect and store credit card details, when you create a booking from your calendar, you can collect credit card details as security in the Payments tab of the booking. You can click here to see if your payment gateway offers this feature.
1. Click on your calendar to create the booking
2. Select participants, options and enter customer’s details
3. Go to the Payment tab
4. From the Action  dropdown menu, select capture credit card details
5. In the Credit card section , input the credit card details
If you have already saved the booking, you won't be able to collect credit card details. You will be able to charge a credit card. Click here for more information