You can change the mobile number in your HDFC Bank account online through internet banking or by visiting your nearest HDFC Bank branch. For the online method, log in to your internet banking account, navigate to the 'Update Contact Details' section, and follow the prompts to enter your new mobile number. You will likely need to authenticate the change through an OTP sent to your existing or new number. Alternatively, you can visit the branch with proof of your ID and request the update, which the bank staff will help you process.
