Firstly register your credit card and create login & passward in HDFC Netsafe.
To go to Registration page Click Here .
Now you will get a Netsafe Passward.
Then select HDFC Bank Master / Visa Credit Card Gateway in Bank Page of the Extension.
Now select the option of Verified by Visa Passward and enter your Netsafe passward.
Then it will not ask for OTP on payment page.