Yes, you can add the company tax registration number in an invoice's header, Jessica.
You can go to the Custom form styles panel to customise an invoice and add the company registration number.
For more details about customising invoices, estimates and sales receipts in QuickBooks Online (QBO): https://community.intuit.com/articles/1768656.
I have articles here about customising sales forms:
I'm confident the steps I've provided can help add the company tax registration number in your invoice's header.
Please reply to this post if you need anything else with customising an invoice. I'm always here to help.
Hi there, @All Season Lot.
Welcome to the Community, and thanks for sharing your concern in this thread.
To clarify, the CRN is an optional thing, and that you'll need to manually add it in the +Custom field so it will show up in your sales form template. See the screenshots below:
Enter the CRN in the field, and ensure to check the box so it will display in the template as shown in the screenshot below:
After that, click the Preview PDF button below to maximize the view. Then, click Done to save your work.
For future reference, you may also want to learn about adding a discount to your sales forms in QuickBooks Online. It has a step-by-step guide in turning on the discount feature and applying it should you want to give out a discount to your favorite customer.
Let me know in the comment below if you have more questions. We're always delighted to help you more.
Thanks for getting back to us, All Season Lot.
The availability of a certain feature depends on the level of subscription. Customization is only available in QuickBooks Essentials, Plus, and Advanced. This can be the reason why you're unable to have that option.
If you're using Simple Start, you can upgrade to any of the subscriptions I mentioned above so you can customise your sales forms the way you want it. Here's how to upgrade your subscription:
I also recommend checking out this article for more details on how to customise invoices, estimates, and sales receipts in QuickBooks Online.
Keep us posted if you need anything else. We're here to help.