Hi renjithramachand,
It sounds like you're looking to change the region for your payment information. If so, know that with iCloud and other Apple services "Not all features are available in all countries or regions." You can find this information and more here: iCloud+ plans and pricing
Additionally, changing your country or region requires waiting until the end of a current subscription, and additional requirements and information can be found below and in the article here: Change your Apple ID country or region
"What to do before you change your country or region
Hope the information helps.
Cheers.