Hello shantanu98,
It sounds like you want to change the country or region for the App Store, correct? We'd love to provide some information.
Just to confirm, did you change the country/region for your Apple ID account using these steps? Change your Apple ID country or region
If so, updating your Apple ID country/region should update for all of your Apple services, on all of your Apple products.
Which device are you using? If you're using a Mac, you can find more information about changing your country or region code in the App Store on a Mac here: Change your country or region code in the App Store on Mac
Take care!