I accidentally marked an invoice paid that was only partially paid. How do I correct

Hello there, kbizadvisor.

Let me share some information about your concern.

In QuickBooks Self-Employed, we're unable to apply for partial payments directly to the original invoice. It's because the product doesn't have a Balance forward feature.

With that, we can only manually duplicate the invoice and modify the details, such as the amount. Make sure to enter the partial payment before saving the duplicate one. Since we've accidentally mark it as paid, we can delete and recreate it. Once done, create a duplicate for the partial payment.

To guide you further, you can follow the steps below:

1. Go to Invoices on the left side.
2. Locate the invoice.
3. Under the Action column, click the drop-down arrow next to the word Send or Send Reminder.
4. Select Duplicate.
5. Enter the partial invoice payment.
6. Click Save.
7. Let's go back to the invoices lists and find the duplicate invoice you've created.
8. Click the drop-down arrow one more time and select Mark as paid. 

Here are the sample screenshots:

Marking the invoice as paid will not automatically record the payments in your Transactions page. We can manually add the partial payment through the help of this article: Manually add transactions in QuickBooks Self-Employed (QBSE).

When time comes that it's fully paid, you can mark the original invoice as paid.

Let me know if you have other questions about it. I'm always here to guide you further. Take care!