An Aadhaar card is required to use a number of services and to validate documents. Your cellphone number must be registered with UIDAI in order to use online Aadhaar-related services. This registration makes it possible to get an OTP for authentication. Your mobile number must be connected to Aadhaar in order to utilize the mAadhaar app. A trip to an Aadhaar Enrolment Center is necessary if your prior mobile number that was registered with UIDAI has been deactivated or if you want to alter the mobile number on your Aadhaar card. Step by step guide:how to change/update your mobile number offline? Step 1: Visit to your nearby Aadhaar Enrolment Centre. Step 2: Fill the Aadhaar Update/Correction form as directed by the Aadhaar executive. Step 3: Give the duly filled form to an Aadhaar executive. Step 4: Pay INR50 fee for the service. Step 5: You get an acknowledgement slip containing the URN.(update request number) Step 6: The URN can be used to check the status of your update r...