My VAT drop down box on billing for expenses is not working?

Let's make sure that you can select a VAT code for your transactions, Guzz5126.

Can you also tell us what happens when clicking the drop-down list for VAT? There are times that too much cache or certain browser issues affect how QuickBooks behaves. Let me share some steps that can resolve some of the most common browser-related issues when working in QBO.

First, log out from your account.

Second, use an incognito/private browsing session or a different browser. Here are some of keyboard shortcuts to quickly open an incognito session: 

• Ctrl + Shift + N  for Google Chrome
• Ctrl + Shift + P  for Firefox
• Control + Option +P if you're using Safari
• Ctrl + Shift + P for Microsoft Edge

Third, log back in and check if the drop-down list for VAT codes is now working. If you're able to do it, follow the steps in this article to delete your browsing history: Clear Cache And Cookies To Fix Issues When Using QuickBooks Online.  

Let me know if you still need more help with this. The Community is always here to back you up and assist you anytime.