IRS Form 5071C is an IRS communication requesting additional identity information. The IRS simply wants to verify that you are the person who submitted a tax return. You will typically receive this letter if your name or social security number associated with it has been received by the IRS forms 1040. If you have received Form 5071C, take the following steps: use the idverify.irs.gov website for security identification. It is a secure website run by the IRS where you can enter your information and electronically verify your return or just call the number listed on your Form 5071C letter. The specialist in the call center will help you navigate the process. If you have not filed the return on Form 5071C, you can either inform the IRS on the website or call the number on the form. The website and telephone number are for the identification of tax returns only. No option can help you with the status of tax refund or other problems.