Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hello, thank you for reaching out to Microsoft Q&A.
If you are looking to change the Region and Payment method for your Microsoft Office 365 Subscription, first you will need to cancel the existing subscription.
Go to https://account.microsoft.com/services/microsoft365/billing (manage your subscriptions page), and sign in with your Microsoft account.
Click Cancel Subscription.
Please review the section at the top of the cancel page and what benefits you will lose.
Once done, select "I don't want my subscription" at the bottom.
Once the subscription is canceled and has expired, you can purchase the Microsoft Office 365 subscription again. You can add a new Payment method to your Microsoft account.
Also, sign in with your Microsoft account here to change the country, language and region.
https://account.microsoft.com/profile
If you're having any issues while making a purchase, you will have to reach out to Microsoft Office 365 support directly.