How do I mark invoice as paid. Thanks

Welcome to the Community space, @michaelbassett.

Marking your invoice as paid in QuickBooks Online is quick and easy. It's my pleasure to help you with the process so you can manage your transactions seamlessly.

There are a few different ways to mark an invoice as paid. You can go to the Sales tab and select Invoices or create a Receive Payment  to mark it as paid in QuickBooks. Let me show you how:

1. On the left navigational bar, go to the Sales tab.
2. Select Invoices.
3. Choose the invoice, and then from the Action column, click the Receive payment button.

For the receive payment:

1. Click + New, then select Receive payment.
2. From the Customer drop-down, select the name of the customer.
3. From the Payment method drop-down, select the payment method.
4. From the Deposit to drop-down, select the account you put the payment into. 
5. From the Outstanding Transactions section, mark all open invoices of the customer.
6. Click Save and close.

For more information, check this article: Record invoice payments in QuickBooks Online. Once done go to the All Sales tab to verify the invoices that are paid.

In addition, I've got you these articles in case you'd like to customise your sales forms and reconcile your accounts in QBO: 

• Customise invoices, estimates, and sales receipts in QuickBooks Online
• Reconcile an account in QuickBooks Online

Don't hesitate to leave a comment below if you have any questions. I'll be right here to answer your questions. Stay safe.