Use the HDFC MobileBanking app and activate the card under Debit Card Services
Use HDFC NetBanking and go to Cards or Debit Card activation options
Visit an HDFC ATM and complete card activation or PIN generation
Call HDFC customer care and follow the IVR instructions for activation
Use the card for a first transaction at an ATM or POS if activation is already enabled
Set or generate the debit card PIN through ATM, NetBanking, MobileBanking, or customer care
If required, complete OTP-based verification on your registered mobile number