Hi sonylef,
Welcome to Community! It's important that you're able to add and apply sales tax to your transactions in QuickBooks Online. I'd be glad to assist!
If you haven't done so already, I recommend clearing cache on your browser. If you're still not able to add taxes, I suggest trying another browser such as Safari, Edge, Google Chrome, Firefox or a Private/Incognito window.
Should you require additional assistance, please contact us outside of Community. Our Customer Care team will have the ability to connect with directly, review the unexpected behavior, and escalate it for further investigation if needed.
Schedule a Callback or start a Chat: click (?) Help in the upper right in QuickBooks Online > enter "Contact support" > hit Contact Us > provide a brief summary of your situation > hit Let's Talk > choose Get a callback or Start a Chat.
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Support hours are from Monday to Friday between 9 a.m. and 8 p.m. ET.
Feel free to reach out with any other questions. We're always happy to help!
