A "permanent resident" of the United States is someone who has been lawfully admitted into the U.S. or has adjusted status to that of "legal permanent resident" (frequently referred to as a “green card” holder). Applications for U.S. permanent residency are made by applying to the United States Citizenship and Immigration Services (USCIS). Such applications may be "employment-based" or "family-based." International Student and Scholar Services (ISSS) only files employment-based immigrant petitions.
A U.S. employer based on an offer of permanent, full-time employment normally files employment-based immigrant petitions. Under certain circumstances, an individual who is a recognized expert in a field of specialization may not need an offer of permanent full-time employment to apply. Current regulations of the USCIS provide general categories under which an employment-based immigrant petition may be filed. A brief summary of these can be found in the administrator's section.