Hi there, @frankthepilot.
I'm here to help share insights about your invoices in QuickBooks Online so you can view their transaction detail accordingly.
You did not change a setting, invoices already sent to your customers will show the same options as what is shown on paid and closed ones. These options are More actions and Edit invoice, each has its boxes.
Clicking the Edit invoice options will show the transaction detail and you're now able to view the items on your invoices. Kindly read and use this article to learn more about invoices: How to Create and Send Invoices in QuickBooks Online?
I'm also adding this reference with the steps in creating a document for your customers showing what is due for a certain number of days: Create and Send Statements in QuickBooks Online. This way, you can remind them and let them prepare the needed payment for your invoices.
I've got you covered if you have questions about QuickBooks invoicing. Don't forget to include my name, @JonpriL, in your reply in the comments below so that I can get back here and lend a hand. Stay safe!