Generally, a citizen of a foreign country who wishes to enter the United States must first obtain a visa, either a nonimmigrant visa for temporary stay, or an immigrant visa for permanent residence. Temporary worker visas are for persons who want to enter the United States for employment lasting a fixed period of time, and are not considered permanent or indefinite. Each of these visas requires the prospective employer to first file a petition with U.S. Citizenship and Immigration Services (USCIS). An approved petition is required to apply for a work visa.
Labor Certification – Some temporary worker visa categories require your prospective employer to obtain a labor certification or other approval from the Department of Labor on your behalf before filing the Petition for a Nonimmigrant Worker, Form I-129, with USCIS. Your prospective employer should review the Instructions for Form I-129 on the USCIS website to determine whether labor certification is required for you.