how will igst or gst will apply automatically according to place of supply state

Hi there, mehul9k.

For now, the option to automatically assign GST or IGST tax codes based on the supplier's location is unavailable. You will need to manually select the correct tax code when creating an Expense or Check transaction in QuickBooks Online. More details about tracking GST are discussed in these articles:

• QuickBooks For GST
• How GST Impacts QuickBooks Users

We have taken note of your feedback and we'll take it as a feature request. You can also visit this site where you can see all the latest updates and newly added features in QBO: The QuickBooks Blog.

Lastly, let me share this guide that can help you process your-end tasks in QBO: QuickBooks Online Year-end Guide And Checklist.