The first option to charge a customer’s credit card is to click the “Customers Tab“, then click “Charge Cards On File“.
Enter the amount you want to charge the card for and click the green “Charge Card” button.
Charge Card From Payment Screen
Another way to charge a card is on the “Finance Tab“> Payments
Click the green “+Add Payment” button
Select the customer, invoice, date, amount of the payment, then select “Credit Card” as the payment method.
The last step is to click the blue “Add Payment” and then select the card to charge.
Charge Card From Invoice
The last way is to charge the card from an invoice.
Click the green “+Add Payment” button and select “Add Payment And Charge Card“
You will then see the payment page.
It will already have the customer, invoice, and payment type selected. Enter the amount for the payment. 
When finished, click the blue “Add Payment” button and select “Charge Card“
This will charge the card on file and add the payment to the invoice.
