Publication 15
taxmap/pubs/p15-003.htm#en_us_publink1000202289If you are required to report employment taxes or give tax statements to employees or annuitants, you need an employer identification number
(EIN).
The EIN is a nine-digit number the IRS issues. The digits are arranged as follows: 00-0000000. It is used to identify the tax accounts of employers and certain others who have no employees. Use your EIN on all of the items you send to the IRS and SSA. For more information, see Publication
1635, Understanding Your EIN.
If you do not have an EIN, you may apply for one online. Go to the IRS.gov and click on the
Apply for an Employer Identification Number (EIN) Online
link. You may also apply for an EIN by calling 1-800-829-4933, or you can fax or
mail Form SS-4, Application for Employer Identification Number, to the IRS. Do
not use a social security number (SSN) in place of an EIN.
You should have only one EIN. If you have more than one and are not sure which one to use, call 1-800-829-4933 (TTY/TDD users can call 1-800-829-4059). Give the numbers you have, the name and address to which each was assigned, and the address of your main place of business. The IRS will tell you which number to
use.
If you took over another employer's business (see
Successor employer
in section 9), do not use that employer's EIN. If you have applied for an EIN
but do not have your EIN by the time a return is due, write "Applied For" and
the date you applied for it in the space shown for the number.