How to change the country/region from the setting. It shows I cannot change the information at this time

There are a lot of requirements that you need to fulfill in order to have you country or region changed. See this requirements:

• Spend any remaining balance in your Apple ID. If you’re not sure whether you have a balance, check your Apple Account balance.
• Cancel your subscriptions and wait until the end of the subscription period. 
• Wait for any memberships, pre-orders, film rentals or Season Passes to end, and wait for any pending store credit refunds to be processed. You can cancel a pre-order.
• Make sure you have a valid payment method for your new country or region. See which payment methods you can use.
• Re-download your apps, music, films, TV programmes and books on any devices you might use to play or read them in the future. Some types of content may not be available in your new country or region. Find out what types of content and service are available in your new country or region.

If you have met all of these requirements and you're still getting the message that your store front information could not be changed please Contact - Official Apple Support for further assistance