You can charge the stored details by raising an invoice -> adding items to the invoice -> Payments + -> In Method, choose the Card Ending XXXX option -> OK.
Clicking OK will charge the card and you will be notified of any failed payments.
If you do not see the option for a stored card, you will need to first add the card to the client file. Steps to do this are here.
If you would like to set up a recurring payments, please click here.