Banking - Category Questions

• I want to transfer large amounts securely but noticed RTGS is not enabled on my account yet. How can I activate RTGS in HDFC Bank and what are the steps involved for online or branch-based activation?
• I need my CRN number for a Kotak Bank service but I can’t seem to locate it anywhere. How can Kotak customers find their CRN number using mobile banking net banking statements or customer support?
• I have a bank account but only know the account number not the branch details. How can someone find the branch name of a bank using account information IFSC code passbook or online banking tools?
• As an NRI trying to manage finances in India I often hear about NRE and NRO accounts but struggle to differentiate them. What is the difference between NRI NRE and NRO accounts in terms of usage and taxation?
• After receiving my Karnataka Bank debit card I realized it needs activation before use. Without visiting a branch how can I activate my KBL debit card online and what details or verification steps are usually required?