When you bill with a credit card, with the client’s permission, you can store a token representing that card. Then you can bill to that card for the next service without the client card present.
The card details are stored fully securely according to PCI-DSS card security standards so you and your client know they are safe. You can see just the last 4 digits and the expiry date for reference.
See Credit Card Billing for more details.
The Black Church, Dublin, Ireland