I have Quickbook online. I have my chart of account and sales tax codes and suppliers. I cannot choose a category or tax code when creating expense ? the fields are empty

Hello usermastrostefano-co,

Great to learn you're a part of the QuickBooks family! QuickBooks is a powerful software program which helps you stay organized making it easy to complete your work in a timely manner. I'd be glad to assist you with figuring out what's going on in your account. 

Based on what you've described, I highly recommend checking to see if you've set up your taxes correctly as it's important you're able to collect and remit sales taxes. Here's how to set up taxes on your account: 

1. From the left menu, select Taxes.
2. Select Sales Tax. (Tip: If you use payroll in QuickBooks Online, you may need to select Sales Tax as opposed to Payroll Tax.)
3. Select Manage sales tax.
4. Select Add tax.
5. Under What type of tax do you want to add? select Add next to one of the below options and follow the prompts to complete set up.

Check out this helpful article for more info: https://quickbooks.intuit.com/learn-support/en-ca/taxes/how-to-set-up-a-new-sales-tax-code/01/261929.

If you're still having issues after setting up the taxes, I recommend clearing cache and cookies. Clearing cache and cookies is the go to remedy for browser issues. Here's an article which shows you how to do that: How to clear cache and cookies. If this doesn't work, I suggest using a private/incognito window to see if that works instead.

Give this a try and keep me posted on how you make out. I'll be one message away in case you need anything else.