Visit your nearest HDFC Bank branch with a valid ID proof
Fill out the mobile number update request form
Submit the form along with your ID proof
Complete any required verification process
Wait for the bank to update your mobile number
You may also update it through HDFC Bank NetBanking if the option is available
You may also use HDFC Bank MobileBanking if the feature is available
Contact HDFC Bank customer care for guidance on the update process