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. 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.The hours of operation are 7 a.m. Use this EIN and your name exactly as they appear at the top of this notice on all your federal tax forms. Fill out IRS form SS4 and mail it to the IRS. After applying for an Employer Identification Number (EIN), the IRS will send you an EIN confirmation notice called Form CP575. The EIN confirmation letter is an important document for businesses in the United States. Get to know how to get your 147C letter. The IRS will generate the letter confirming your EIN's validity and send it to the business address on file. The company is sent a letter asking for information about its EIN or Employer Identification Number.