How do I show an invoice paid when the customer paid with a credit card that is my outside credit card processor?

Let me guide you with receiving the invoice payment, Inspector1.

You can follow these steps:

1. Click the New or Plus sign (+) button.
2. Go to Receive payment.
3. Select the customer and the invoice.
4. Under Payment method, select the credit card account.
5. Uncheck the Process credit card box since it's from the outside credit card processor.
6. Click Save and close. 

I'll also include this article to help you learn more about recording payments: Record invoice payments in QuickBooks Online.

Get back to this thread if you need more help with your concern. We'll reply as soon as we can. Take care!

yes it answered the question