The Income Tax feature in QuickBooks Online (QBO) is only available if your tax form is set to Sole trader under the Company type settings in your account, blanchardspawsomepartners.
Here's how to verify your setup:
- Go to the Gear icon at the top and choose Account and settings.
- In the left menu, select Company and go to the Company type section.
- Review the Tax form field and ensure this is Sole trader.

- Click Save, then Done.
After that, return to the Taxes page. You'll now be able to see the Income Tax section. 
For more information about the estimated income tax feature, you can read this article: Understanding Income Tax | QuickBooks Online. It also contains information on who needs to file a Self Assessment tax return.
If you have questions about handling income tax estimates, you can reply to us. We'll be more than happy to help you.