We can perform some troubleshooting steps to resolve the unusual behavior you're experiencing when creating invoices with tax code, noomoo.

Clearing the app's data to refresh the system and eliminate any outdated files that could be causing the issue. This process will free up storage space while keeping your documents and data intact.

For Android:

• Go to the Menu ☰.
• Tap Settings, then Refresh Data.
• Tap YES to confirm.

For iOS:

• Go to Settings, then tap General.
• Tap iPhone Storage, then tap the QuickBooks Online app.
• Tap Offload App.

You can also uninstall and reinstall the app to provide a fresh start with updated settings and fixes. However, if the issue persists after following the recommended steps, I recommend contacting our Live Support team for further assistance when creating an invoice with a tax code.

Meanwhile, you can log in to your QBO account in any supported mobile web browser and perform the task that you need to finish in QuickBooks.

If you have any further questions, please feel free to reply below. We're here to help you.