I have an iPhone 6s Plus. I want to change the country and region but I'm being asked to enter my credit card details, with no other option.
What should I do? Is there an option without entering credit details and changing the store to US?
This Apple support article explains that a valid payment method is always required when changing regions.
When you change the country or region of an existing Apple ID, you must provide a payment method and update your billing options. If you want to remove your payment method after you change the country or region, you can change your payment information to None.
You may be able to set up a new Apple ID for a different region without entering credit card information, but any apps purchased (whether free or not) with that Apple ID would require that Apple ID be signed in to get updates.
To create a new account without a payment method, go to the App Store, iBooks Store or iTunes Store on your device. Tap Get on any free item and follow the steps for setting up a new account. When prompted for a payment method, None should be on the list. If it's not, you must enter a payment method.
I believe its not possible to change to region B once you have set up a credit card in region A unless you have a credit card that is valid in B (or at least thats how I think it works) however i'd expect that apple support can probably change your region for you.
As a small side note, if you don't have a credit card associated with your account you can change region as much as you want (unless you have unused balance)
I don't think its possible, ask apple support.
Edit #1: Decided to quickly google this. Here is a link that probably does a better job at explaining than me. Support.apple.com