There is only a Form 1040. Both the Form 1040A and 1040EZ were removed after tax year 2017.
To enter, edit or delete a 6 digit IP PIN
Click on Federal Taxes (Personal using Home and Business)
Click on Other Tax Situations
Scroll down to Other Return Info
On Identity Protection PIN, click the start button
Or enter ip pin in the Search box located in the upper right of the program screen. Click on Jump to ip pin