The Work Permit. Specialized Qualifications (H-1,H-2a.H-2b)

A person having outstanding qualifications, higher education or an international reputation which can contribute to the enrichment of the American society can obtain the permission to work temporarily to the United States.

In certain fields such as medicine, the applicant will be required to pass examinations. In the fields of arts or sports once the applicant has proven to be well known and to be a person of high integrity, temporary immigration status may be granted.
As far as the time required between the application and the granting of non-immigrant status, it will vary with each case. The H visa is renewable but only allows the right to work and temporarily live in the United States for a period of three years, maximum of six years. 

The Employmentbased preference which we will analyze later, allows a permanent residence in the United States.

The law may require a person to have a diploma in order to apply or this applicant must have a worldwide reputation and must be able to prove fame by showing prizes, articles written about that person, or other proof of renown in his or her field or work.

The Work Permit.

The worker who is not admissible using the above visas can, in certain cases, temporarily enter the United States thanks to a work permit (labor certification).
The American government does not grant a work permit to a foreigner unless local employment recruitment requirements for a given job have been met.
Certain jobs are privileged with regard to others depending upon the time of year and the geographical areas. The number of jobs open as well as the dates of granting the visa are determining factors.
For example, if there is a lack of chefs in a particular region of the United States, there are good chances that a foreigner having such a specialty can obtain a labor certification for that region. This will allow him or her to later obtain a green card.
Some professions are automatically accepted. This is the case of physiotherapists because the Immigration Department has determined that there is a lack of American professionals in that field. This is no longer the case for dietitians who were needed a few years ago. However certain doctors and nurses are now admitted without much difficulty.
But in most of the cases, in order to retain a work permit, a potential American employer must sponsor the foreigner and prove that the job has been offered first to Amefican Citizens having the same qualifications but who are not ready, willing or available to accept the position.