How do I reopen an invoice I closed out by mistake?

You'll have to delete the payment that's linked to the invoice in QuickBooks Online (QBO), @southernservice4. I'm here to guide you how.

You're able to close an invoice when you've received and process its payment in QBO. To reopen a closed invoice, you need to delete the payment that's linked to it by following the steps below:

1. Go to the Sales menu.
2. Choose the Invoices tab.
3. Find the invoice and click the drop-down arrow under the Action column. Then, choose the View/Edit option to open its details.
4. Click the 1 payment made (amount) link at the upper right corner below the PAID payment status and then select the date link.
5. On the Receive Payment window, click the More option at the bottom.
6. Select Delete, then choose Yes to confirm.

I've attached screenshots below for your reference.

After deleting, I'd recommend pulling up the Open Invoices report. This is to verify that the invoice is reopened accordingly. Just go to the Reports menu, then select the said report under the Standard tab's Who owes you section.

Also, you're able to create attractive and professional-looking invoices in QBO. With this, you're able to add the info that matters most to your business. If you wish to know more about this, you can refer to this article: Customize invoices in QuickBooks Online.

Let me know how it goes in the comments below. If you have other concerns about reopening invoices and managing your sales transactions in QBO, I'm just around to help. Take care always.