How do I mark an invoice as paid if they paid via card?

Marking invoices as paid in QuickBooks Online (QBO) is easy, @carnforthcaravan.

If the invoice is paid via card, you simply need to choose this option when recording the payment in QBO. I'm here to show you how:

1. Sign in to your QBO account and click the +New button.
2. From there, choose Receive Payment.
3. Select the customer's name from the Customer dropdown.
4. Check the box beside the invoice they pay.
5. Then, click the Payment method dropdown and choose Card.
6. Once done, select Save and close. 

I've attached this article for your reference in record invoice payments in QBO: Record invoice payments in QuickBooks Online. It also includes steps on how you can enter a partial payment for an invoice.

You can also print or send payment receipts to your customers. Here's how to do it:

1. Go to the Sales menu and choose Customers.
2. Look for the customer you recently recorded a payment with. Click the name to open.
3. Under the Transaction List tab, find the payment transaction.
4. Click it to open.
5. Select the Print option at the bottom part of the page if you want to print the receipt.
6. Choose Save and send button if you want to send the receipt to your customer.

If you have further questions about marking the invoice as paid in QBO. Feel free to leave a reply below. It's my pleasure to answer them for you. Take care always.