Welcome to the Community, @Anonymous.

I can share some insights about the printing invoice in QuickBooks Online.

Paid and unpaid invoice have different printed views. As mentioned, you'll have to unlink the payment transaction to its invoice to remove the paid stamp:

1. Open the payment transaction.
2. Uncheck the invoice transaction.
3. Click Save and close.
4. Open the invoice transaction again and print it.

Automatically, there will be an unapplied payment under the customer name.  To close the invoice, follow these steps:

1. Click the Plus icon.
2. Choose Receive Payments.
3. Select the customer name.
4. Put a check mark on the invoice transaction and Unapplied Payment.
5. Click Save & Close.

That should keep you going today, jagrre. Let me know if there's anything else you need about invoices. I'm still here to offer more help. Have a good one!