Why doesn't the invoice number print out on the invoice

Welcome to the Community, Mark.

I'll help you print the invoice number in your invoices.

Let us first review the invoice template and check if the option to show the invoice number is enabled. If not, you can follow the steps below to turn it on:

1. Click the Gear icon, then select Custom Form Styles.
2. Choose the default invoice template from the list, then click the Edit button.
3. Go to the Content tab and select the Header section.
4. In the Form section, put a checkmark in the Form numbers checkbox.
5. Click Done.

You can then try to print an invoice and see if the number will show.

For future reference, you can read this article to help you customize sales forms in QuickBooks Online: Customize invoices, estimates, and sales receipts in QuickBooks Online.

Feel free to click the Reply button below if you have questions about managing invoices in QuickBooks Online. I'm always here to help. Have a great day.