First, you have no choice but to print, sign and mail your return to the IRS "with" the W-7 included. On the tax return, in the space for her SSN write "NRA". that does it. Just mail the package to the IRS and wait. Expect 6-8 weeks for your refund, if you have one coming. The ITIN will come in a separate mailing, and takes 3-4 weeks for that.