Visit your SBI branch with a valid ID proof and your passbook/account details
Ask for the mobile number update form
Fill in the new mobile number correctly
Sign the form as per bank records
Submit the form to the bank official
Complete any required verification, if asked
Wait for the bank to update your mobile number
Receive confirmation on your new mobile number
Use SBI Internet Banking or YONO only if mobile update is available through your branch-linked process or approved online method