You must update your Paytm-linked phone number in your account to get the reward credited to your wallet directly. 

Step 1. Go to My Account > Referral Rewards 

Invite your friends and family to e-file on ClearTax. More, the better. 

Step 2. To get the reward directly to your Paytm wallet, scroll down and update your phone number. 

Step 3. Enter the number twice and confirm. Remember, you cannot change or edit the number later. So enter only the phone number to which you want to receive the money. 

That's it :) Get Rs.30 each time a friend you referred e-files on ClearTax.