Thanks for posting here, @sandysales.

The numbering of products or services added to the invoice is only visible when you're creating the transaction within QuickBooks Online (QBO). If you want this to show when printing or emailing the form to your customers, the option is unavailable. Please see the screenshot below for reference:

As a workaround, you can use the Description column and manually enter the numbering there. On the other hand, you can also edit the item and add its corresponding number. 

I also appreciate you sharing your ideas about adding this feature. We'd love to hear more of your insights regarding this so I recommend sending feedback to our product developers. This way, they can further review which parts of the program need enhancements and consider adding them to future updates. Please refer to the steps below:

1. In your QBO account, navigate to the Gear icon.
2. Next, select the Feedback option.
3. From there, enter the details of your product comments, suggestions, and requests. 
4. Then, click Next to submit. 

If you have any other concerns about managing your product items in QBO, please don't hesitate to post a reply below. I'm always here ready to lend a hand. Have a good one and keep safe.