Upwork doesn't make these kinds of decisions, and it doesn't answer these types of questions.
Upwork tells freelancers that they need to be legally allowed to work. That's it.
Upwork tells freelancers that they need to consult with local experts and authorities in order to answer the question of if they are allowed to work.
Upwork will ask that you comply with whatever regulations apply to you and your particular situation. Upwork will NOT ask for an EAD or other related documents.
According to your profile you are still in India, so I don't think the problem of whether you are allowed to work not in the U.S. arises just yet. If you have the right to work in India, then you have the right to work on Upwork and to work for any client in the world.
If you are about to emigrate to U.S. , then you must find out from official sources what your options are and how long you have to wait before you can legitimately work as a freelancer in that country.