Aliens who wish to seek employment in the United States have several options by which they can apply for a work permit, or an Employment Authorization Document (EAD).
Adjustment of status application
Because it can take years to receive permanent residency status after filing an adjustment of status application, the BCIS allows aliens to apply for work permits while their adjustment of status applications are pending. The permits are valid for one year, but may be renewed so long as the adjustment for status application is still pending.
Temporary Protected Status
Certain countries are designated by the United States Congress as being under Temporary Protected Status (TPS). Usually this is because of an ongoing armed conflict in that country, an environmental disaster, or some other catastrophic but temporary condition that makes return to that country unsafe. When an alien’s country is placed under this designation, he or she may apply for TPS. The designation expires when Congress rules that people may safely return to that country. When the TPS designation is lifted, the status of aliens from that country will return to what it was prior to their TPS designation.
Note: On its own, temporary protected status does not make a person eligible to apply for permanent residency status.
Non-immigrant work permits
Certain aliens may be eligible to enter the United States and work for a period of time. Visas may be granted to college-level professionals who have job offers in the United States (H-1B visa), to executives, managers or employees who are transferred to a United States branch of their company (L-1 visas), to traders or investors doing business in the United States (E-1 or E-2 visas), to people traveling on business (B-1 visas), and to people who work for religious organizations (R-1 visas).
The various types of non-immigrant work permits are discussed elsewhere on this site.