W7 Form IRS
Use Form W-7 to apply for an IRS individual taxpayer identification number (ITIN). You can also use this form to renew an existing ITIN that is expiring or that has already expired.
An ITIN is a 9-digit number issued by the U.S. Internal Revenue Service (IRS) to individuals who are required for U.S. federal tax purposes to have a U.S. taxpayer identification number but who do not have and are not eligible to get a Social Security number (SSN).