ITIN FOR F2 VISA HOLDER

There's a 5 year exempt period for a student on an F1 visa (and student's spouse F2) and therefore ineligible to file the 1040 and ineligible to file jointly.  Check Pub 519 if there are any exceptions to allow them to presume otherwise, don't recall without looking it up.

***Should add, except for students from India and I remember one other country...used to prepare many 1040NRs but it's been years now.  Check the tax treaty publication too.

As Taxprohere says, there are various rules and time limits about F1/F2 being exempt individuals whose US days are exempted for SPT purposes.  Assuming they are still considered exempt individuals and NRA's, they won't be able to elect MFJ filing.

Normally, foreign nationals would try to avoid having their worldwide income fall within the US tax net by remaining an NRA.  Is there any special reason why they want to file jointly as resident aliens?

If the wife needs to file a US return, she could be eligible for an ITIN.