Starting January 1, 2016, if your dependent received an Identity Protection PIN (IP PIN), you will need to enter this PIN on your tax return if you e-file. The IP PIN does not need to be entered if paper filing.
According to the IRS FAQs about the Identity Protection Personal Identification Number (IP PIN) webpage:
A17: This is determined by how you file.
E-File Return: As of January 1, 2016, if you claim one or more dependents that have an IP PIN, you must enter their IP PIN on the following e-File tax forms:
Your e-File return will be rejected if you fail to enter a dependent's IP PIN.
Note: If someone can claim you on their tax return as a dependent and you have an IP PIN, you must share your IP PIN with them if they e-File.
Paper Return: You don't need to enter an IP PIN for your dependent(s) when filing a paper tax return.
To enter your dependent's IP PIN:
Note that any link in the information above is updated each year automatically and will take you to the most recent version of the document at the time it is accessed.