Hi there, @gsobsey.

The Form numbers option may be selected in the invoice template. Let's verify it by following these steps:

1. Click the Gear icon located in the upper right-hand corner.
2. Under Your Company, click Custom Form Styles.
3. Click the Edit link of the default invoice template.
4. Click the Content tab, and click the header part of the invoice to expand more options.
5. Under Form, if the Form Numbers box is checked you may uncheck it so the invoice number won’t show on the customer’s emails.
6. Click Done.

Then, try printing your invoice and check if the invoice number shows up.

 Check out the How to Customize Invoices in QuickBooks Online article for additional resources. It contains screenshots and complete information on how to change the layout, design, and data fields that show on the invoices.

If you need further assistance with the customization process, post a comment below. I’ll get back to help and make sure this is taken care of for you. Have a great rest of the day.