I want to change the way Quickbooks automatically calculate the tax on invoice creation based on tax settings. I want to call a 3rd party service to query the tax.

Thanks for joining the Community space, @uservu-quanghoa.

You can contact the third party service for further assistance with the integration to QuickBooks Online. They can also help you in setting the calculation to ensure the accuracy of your invoices taxes.

Also, I'd suggest posting this question to our Intuit Developer Community. It's a place where different developers and coders help each other with app development, integrations, and programming. They can also further check if we can directly integrate the webpage with a third-party app.

Here's how to get in touch with them:

1. Go to this link: https://developer.intuit.com/.
2. Scroll down, then click Contact us under the Intuit column.
3. Select your subscription.
4. Click Ask A Question.
5. Sign in to your account, then follow on-screen instructions.

To stay current on all QuickBooks news and latest updates, you can visit the QuickBooks Blog site. It provides articles depending on which topics you've selected.

Also, you may consider checking this article attached in case you have questions concerning QuickBooks and its functions: Getting started with QuickBooks Online.

If you have additional concerns or need anything else, let me know. I’m always here to help. Have a good one!