Commonly known as a US work visa, H1B is a nonimmigrant, employment-based visa that is granted to an eligible temporary worker. H1B must have a US-based, specialty occupation at hand, and your employer must apply for your H1B visa petition with the US Immigration Department. Once approved, this petition is a work permit in the form of I-797 which allows you to obtain a visa stamp and begin work in the U.S. for that employer.