I have quickbooks online. When I add a new customer. The tax/vat tab is missing. So I can't add the customer vat number to the customer profile. How do I fix this?

I can see how the option to enter tax information in your customer's profile is convenient for you, books-pegasus-sy.

While the option to enter the customer's VAT registration number on their profile is unavailable, you'll want to add it to the sales form template. So every time you create an invoice, you can manually enter the number.

 Let me show you how: 

1. At the upper-right, click the Gear icon and select Custom form styles.
2. If you have an existing template, click Edit under it or click New style to create a new one.
3. Click the Content tab and click on the Header section of the sample template.
4. Under the Display section, you can click the +Custom field and check the box and name it something like VAT number.
5. Click Done.

I've taken note of this suggestion so we can apply it to future updates. You can also send on your end by following these steps: 

1. Click the Gear icon and select Feedback.
2. Enter the description of your feedback.
3. Click Continue. 

If you need to do other tasks in QuickBooks, our articles can help you out. Look for them on our Help Articles page.

Let me know if there's anything else that you need help with. Take care!