This isn't a ProSeries user question. It's a bit beyond this.

"Can they apply for ITIN?"

It isn't clear which party is "they" for the issue."Individuals in F-2, H-4, TD or O-3 status will not be issued Social Security numbers." TN means they get SSN and TD means they get ITIN, as I understand it, but you need to do the specific research yourself. It isn't clear if the issue relates to working?

https://www.irs.gov/help/ita/am-i-eligible-to-apply-for-an-individual-taxpayer-identification-number

https://www.irs.gov/individuals/international-taxpayers/taxpayer-identification-numbers-tin