I am using the Quickbooks Self Employed and there is no option to show outstanding balance or previous payment on my customers invoices. How do I turn this option on?

Allow me to share some information about your concern, @slalomskie.

To begin with, may I ask if your customer made a partial payment, which makes you want to see the outstanding balance? If so, please know that we don't have the option to do this in QuickBooks Self-Employed.

As a workaround, we can enter your customer's partial payment as negative. 

Here's how: 

1. Navigate to Invoice. 
2. Choose the invoice with partial payment, then click Edit.
3. Add another line item with the same item.
4. Enter the amount of the payment as Negative.

After this, you can categorize the transaction payment as Income. 

I've added some screenshots for your visual reference: 

Moreover, please know that QBSE Invoicing is merely for creating, printing, and emailing invoices. It doesn't show how much each customer accumulates (balances and payments, or the totals of both.

Additionally, you can use Schedule C to report your income and expenses. 

Let me know if you have further concerns about invoice payment or any QuickBooks-related concerns.