The only two ways to get an EIN Verification Letter (147C) is to call the IRS at 1-800-829-4933, or to mail the IRS a written request. How to Contact the IRS for EIN Verification Letter?Use Form SS4 to apply for an employer identification number (EIN). An EIN is a 9-digit number (for example, 12-3456789) assigned to employers. This EIN confirmation letter is called CP 575, and the IRS only mails the letter to the mailing address listed on line 4 of the SS-4 application. This document provides detailed instructions on how to obtain a confirmation letter (147C letter) for your EIN. Use this tool to get an EIN directly from the IRS in minutes for free. Thank you for applying for an Employer Identification Number (EIN). The IRS will generate the letter confirming your EIN's validity and send it to the business address on file. You'll be requested to provide the number when filling out taxes and payroll forms.