Thanks for visiting the Community, @arjunads.

In QuickBooks Online (QBO), you can add a custom tax that will let you create a new tax agency and rate. Here's how to do it:

1. In QBO, go to the GST menu at the left pane.
2. Click the Add tax option at the top right, then tick Custom tax.
3. Enter the necessary information.
4. Hit Save once done.

For more information about the process, consider checking out this article: GST Settings Overview.

Reach out to me in the comment section below if you have any other questions or concerns. I'm more than happy to help. Have a good one!