U.S. work authorization isn't required to work for a U.S. company if the worker will be working remotely outside the U.S. Regarding her work visa options, they are limited. The only option immediately available is the O-1 visa, which is for people of "extraordinary ability," a high standard but attainable by many talented professionals. The H-1B "professional worker" visa is much easier to qualify for but it's only available once a year and via a lottery so it's not a realistic option. If she really wants to work for a U.S. company remotely or in the U.S., then she should have a consultation with an immigration attorney and have her background evaluated.