IDnotify is part of the optional Max bundle that you would have selected prior to filing the 2016 tax return using TurboTax.
See this TurboTax support FAQ for the Max bundle - https://ttlc.intuit.com/questions/2924462-what-is-max
See this TurboTax support FAQ for accessing the Max bundle benefits - https://ttlc.intuit.com/questions/2924453-how-do-i-access-my-max-benefits
For IDnotify you should be able to sign onto the IDnotify website using the same userID and password you used to create the 2016 TurboTax online account - https://ttlc.intuit.com/questions/3372443-how-to-login-to-idnotify
If you are unable to access the IDnotify account then go to the IDnotify contact website for assistance - https://www.idnotify.com/contact/
