Glad to have you here, @vamsi-ipageums-c.
I'm here to help you with your tax concern.
You'll have to create a GST again then make sure to select the IGST tax once you create an invoice. Let me walk you through the steps on how to create IGST tax. Here's how:
Please check these resources to learn more information on how GST works in QuickBooks Online:
Feel free to post a comment below if you have any other concerns. We're here to help.