Final answer:
Immigrants need a visa to legally work in the United States, following immigration policies that focus on skilled labor and compliance with employment authorization verification through the I-9 form.
Step-by-step explanation:
Immigrants are allowed to enter the country to work when they have a visa. In the context of U.S. immigration reform and workforce regulations, the Immigration Reform and Control Act of 1986 implemented the requirement for employers to verify the identity and employment authorization of their employees using the I-9 form. Employers are also responsible for ensuring that they do not knowingly hire undocumented aliens, which is illegal under this act. Skilled immigrants, particularly those who fulfill high-skill labor shortages, may be eligible for specific types of visas, such as the H1B visa for specialty occupations, reflecting a priority in immigration policy that values high levels of education and job skills.