On the invoice, is there a way that I can charge a clients credit card internally or from the back end?

Welcome to the QuickBooks Community, urbanmopservices! I'd be happy to provide some information on charging clients.

If you use QuickBooks Payments to process payments, your customer can simply click on "Pay now" within their invoice. If you prefer processing the credit card from your end, you can do this by following these steps:

1. Click the "+ New".
2. Select "Receive payment".
3. Choose a Customer from the drop-down, then select a Payment date.
4. In the "Outstanding Transactions" section, select an open invoice to apply the payment. To take a partial payment, change what's in the Payment field.
5. From the "Payment method" drop-down, click on "Credit Card".
6. Select Enter credit card details.
7. Enter the credit card info.
8. Optional: To save this customer's credit card, select Use this credit card in the future for this customer.
9. Click "Use this info" or "Save" then Select "Process credit card".
10. Hit "Save and close" or "Save and new".

Here's an article for reference.

If you have any other questions, feel free to reach back out here.