For including the IP PIN in your tax return, see: How do I add or remove my 6-digit IP PIN?
@glavis
Please see the posts above for how to confirm your identity. If you did not receive a letter, it may not have been from the IRS. Only respond to the IRS. To verify your identity, go to: Identity Verification for IRS Letter Recipients | Internal Revenue Service.
Otherwise, see: What to do if you suspect tax-related identity theft.
@Valerysla
