Why supplier TIN No do not appear in the VAT report ?

Hi, mohamedem93-gmai.

Welcome to the Community. I'm here to help you run the VAT report with the supplier's TIN no in QuickBooks Online.

You can customize the report by adding the VAT Registration No. of Supplier in the column. Here's how:

1. Go to Reports.
2. Choose VAT Detail Report. 
3. Tap Customize Report.
4. Put a checkmark to VAT Registration No. Of Supplier.
5. Hit Run Report. 

If the VAT no. is unavailable after following the steps. I recommend performing troubleshooting steps to isolate this issue. You can try using another browser or a private window. Unexpected issues in QuickBooks are sometimes affected by the amount of data stored in the cache. This is because the regular browser will constantly overwrite itself and will remove history unless done manually.

The incognito mode will not save any history, so it's a great place to identify issues in the browser. Use these keyboard shortcuts to launch a new private window:

• Google Chrome: press Ctrl + Shift + N  
• Mozilla Firefox: press Ctrl + Shift + P
• Safari: press Command + Shift + N

If this works, I suggest clearing their regular browser's cache to refresh the system. If the issue remains, I propose using other supported browsers. This way, we can verify if this is a browser-integrated issue.

For additional reference, I've added a link you can visit to learn on how you can manage VAT rates: How do I set up sales GST/VAT rates and use them on forms? (International QBO)

Leave me a comment below if you have any additional concerns about VAT Reports in QuickBooks Online. I'll be more than happy to lend a hand.