H-1B is a USA Immigration Service visa classification that permits aliens to be employed in the United States up to six years in a specialty occupation, including occupations in information technology.
To be eligible for an H-1B visa, an alien must have a sponsoring employer.Fields in which specialty occupations exist for which H-1B visas have been permitted include but are not limited to architecture, engineering, medicine and health, accounting, and the arts, as well as information technology.
An employer is required to state or demonstrate that a USA worker will not be displaced by the H-1B applicant. In addition to the H-1B workers, up to 20,000 non-U.S. residents who earn a master's degree or higher from a U.S. institutionof higher learning will also be allowed temporary work visas.

Foreign professionals with specialized knowledge, such as scientists, engineers, programmers, research analysts, management consultants, journalists, accountants, and others with Bachelor's or equivalent degrees.
Professional Nurses entering the U.S. to perform complex job duties or supervise nursing operations.Professional fashion models.

Eligible persons: nurses going to work for up to three years in health professional shortage areas.

1. have a full and unrestricted nurse's license in his or her home country, or have received nursing education in the United States;
2. have passed an appropriate examination (as determined by the U.S. Department of Health and Human Services (HHS)), or have a full and unrestricted license to practice as a registered nurse in the state of intended employment;
3. be fully qualified and eligible under all state laws and regulations to practice as a registered nurse in the state of intended employment immediately upon admission to the United States.
The procedure for an H1C is somewhat similar to the procedure for an H1B. In addition to the attestation that must be filed with the DOL, a petition must also be submitted to the USCIS. More than one nurse may be included on a petition.H1C nurses may be approved for a period of admission to the United States of up to three years.
Upon the expiration of the admission period, the status may not be extended.

Temporary agricultural worker

The H-3 Visa enables individuals to train in the U.S. in 'any field of endeavor'.This includes agriculture, technology, communications and governmental leadership.
The H-3 Visa is not self-petitioning; the employer must submit the petition on behalf of the trainee.
The H-3 does not cover individuals seeking graduate medical training.However, medical students on vacation in the U.S. may be eligible for the H-3 Visa.
The employer must provide certain evidence about the training, including a description of the training program, compensation (if any) and reasons why you need the training.