You can link adhar by visiting a store or just from mobile or internet. The notes here are specific to Airtel, should be similar for other providers too.

1.     Visit the nearest Airtel Store with your Aadhaar number to complete the re-verification process. You will receive the verification code (OTP) on your Mobile that would be authenticated during re-verification process.

 2.     Dial 14546 from the number which needs to be verified and follow instructions. 

We will list down shortcuts for checking Talktime Balance, Data Balance and More with BSNL. We have verifying this against Kerala BSNL number, but will try to update details for other states based on request. Please leave a comment. 

BSNL Kerala -  Talktime Balance, Data Balance and More

*123# - Main balance

*124*2# - STV Balance (e.g. Data balance left for the day in STV333).

One of the features that many users want from whatsapp is to use it for both the sims in a dual sim phone. However Whatsapp does not support this feature as of now. However with MIUI 8, you can install not just two, but three whatsapp accounts.