Generally, in order to work in a specialty occupation, you are required to have H-1B visa. It requires a higher education degree or its equivalent including fashion models of distinguished merit and ability and government-to-government research and development, or co-production projects administered by the Department of Defense. It requires that your prospective employer 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.
Some temporary worker categories are limited in total number of petitions which can be approved on a yearly basis. Before you can apply for a temporary worker visa at a U.S. Embassy or Consulate, a Petition for a Nonimmigrant Worker, Form I-129, must be filed on your behalf by a prospective employer and be approved by USCIS.