You can easily link your Aadhaar for the first time simply by following below steps:
Visit UIDAI’s website https://uidai.gov.in/ or nearest Aadhaar Seva Kendra. You can also dial 1947 to know more about Aadhaar services.
Once you visit the Aadhaar centre, you need to fill the required information in the form given by them and make sure to provide the current mobile number which you wish to link it with Aadhaar.
Submit the form and help the representative with your biometrics to verify
Post biometrics authentication done successfully you will get acknowledgement receipt
This receipt has URN (Update Request Number) by which you should be able to track the status of your request
Once your mobile number is linked with Aadhaar successfully you can avail all the services of Aadhaar.
Also you need to pay a fee at the Aadhaar Enrolment Centre for the service.
Note: You cannot link mobile number with Aadhaar online as currently UIDAI does not provide such facility. Hence, it is mandatory to visit the Aadhaar Centre if you wish to link your mobile number with Aadhaar for the first time.