ITIN is not a standalone application. As a Certifying Acceptance Agent (CAA), I submit both the ITIN application and tax return to the ITIN office in Austin, TX. After the ITIN is issued, the personnel at the ITIN office will inscribe the ITIN on your tax return. They then forward it to another department for processing. You typically cannot e-file your federal return in the year you apply for an ITIN unless you needed an ITIN for other reason than filing a tax return. However, you can E-file your state return after getting ITIN, and e-filing will be available to you from the following year onward.