After you file

The 5071C letter means that the IRS has received your return, but needs more information from you to verify your identity.

You can do either of the following:

• Go to Identity Verification Service and follow the online instructions.
• Call the IRS toll-free on 800-830-5084 for Identity Verification.

For either option, you’ll need a copy of your prior year tax return, current return, and supporting documents like W-2s, 1099s, or Schedule C. 

If you didn’t file the return in question, choose either option to notify the IRS.