Your spouse must get a certified copy of her passport from the agency that issued it in her country, or she must send the original document with the W7 to the ITIN processing center. A notarized copy will not be accepted.
You do not need to send proof of marriage or her birth certificate with the application. You do need to send her original signature on the W-7, they will not accept a copy.
If she cannot get a certified copy of her passport (it isn't always easy to do so), and she's not willing to send the original with the W-7 application, you can see if there is a Certifying Acceptance Agent near her who can assist with completion of the Form W-7 that she can forward to you. You can find a list of those by country HERE
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
