A sample of IRS Form 147C is available at 147c.org. The IRS does not provide online delivery of Form 147C, in the interest of protecting the taxpayer's sensitive information. The IRS only delivers the form by fax or mail. The sample letter comes from a public domain source.
The IRS uses Form 147C to connect employer identification numbers and taxpayer identification numbers with the name of the business. Before the IRS began requiring the form, confusion caused by multiple taxpayer identification numbers, coupled with multiple corporate entities, led to erroneous reporting and even deliberate underreporting of banking information. You can call the IRS at 800-829-4933, as of 2015, to obtain a form.