There is no option to put the tax registration number of the customer

This is a reported issue, @info1571.

Currently, our product engineers are working on an investigation to help determine the root cause of this unexpected behavior. Once completed, they'd be able to release a permanent resolution. 

In the meantime, I'd recommend contacting our Technical Support Team so you'd be added to the affected users' list. Just provide your full name, updated email address, and this investigation number: INV-57356. 

Here's how to contact us:

1. Go to the (?) Help menu.
2. In the QB Assistant enter the topic you need help with. You can also enter questions.
3. Select Contact Us.
4. Give us a short description of your concern. 

5. Choose a way to connect with us:

   • Start a chat with a support expert. Live chat 24/7 (M-F).
   • Ask the community available 24/7 (M-F) to get help from businesses like yours.

Once update is available, you'd be notified through email. Also, it will be applied directly to your account. You can browse this link to view different articles that help you guide in managing your books: Help Guide for QuickBooks Online.

Get back to us here if you have other questions or concerns. I'm always here to help.

The Tax info tab is missing.

Please advise

Hello, info1571. 

Thank you for reaching back to the Community. As mention by my colleagues above, Currently, We have an ongoing investigation about the tax information that can be entered is missing in QuickBooks Online. Rest assured, our software engineers are working hard to resolve this issue permanently.

To ensure you'll get an update about the resolution status, I recommend reaching out to our Technical Support Team. They have to collect personal data to add your company and product to the list of affected users. We'll be sending you updates via email once we get this sorted out and I'll also keep this thread on track. Provide this INV-57356 for easy tracking. 

 We appreciate your patience while our engineering teams are trying to sort this out. Stay safe!