@QasimRashid Wait, I'm a little confused. How can undocumented migrants pay taxes? If they are undocumented migrants, it surely means that they don't have valid papers to work/live in the country, right? Are you saying they pay taxes through third parties? How are they attributed without any valid ID to attach (SSN/NI/any other national identity)?
@QasimRashid For the record, I'm not in the USA. So I don't know how it works there. And, my points were only about taxes on income.
From my experience living in a couple countries, you NEED a valid national identity along with a valid work permit (of course) to be able to pay taxes.