Linking your Aadhar card to a valid phone number is a decision scenario to know the current status, as its official verification is done through a one-time password (OTP) generated in your phone
Updating mobile number for the first time? Go to nearest Aadhaar center to collect the Aadhaar Update/Correction Form or download the form the UIDAI website.
Fill the Form, Mention only the mobile number option need to be updated.
Submit it at the Aadhaar center along with an identity proof. Here a list documents which are accepted
After submission, your bio-metric details would be verified.It would take at least 10 days for the phone number to be updated.
Steps to change mobile number online
In case you want to change the phone numberyou could do it online.This method can be used if you don't use the mobile number used registering with Aadhaar. However, you're already registered phone number linked to Aadhaar need to be functional for generating the OTP.