Foreign workers must obtain permission to work in the US in the form of a valid work visa, employment based green card or employment authorization. The Immigration and Nationality Act includes a range of US work visas and green cards for foreign workers with an offer of employment in the US.
Foreign workers with a temporary offer to work in the US may be able to apply for a temporary non-immigrant work visa, while those with a permanent offer to work in the US may be able to apply for a Green Card. Students and exchange visitors to the US may be permitted to work in the US if they possess a valid student visa or exchange visa.
In order to get a work visa in the United States, you need first to get a valid job offer or a work contract from an employer in the country beforehand. Petition for Non-Immigrant Worker (Form I-129) must be filed for any prospective “H" Visa applicants by the employer; processing fees apply. Upon approval by the immigration authorities, the employer will receive an official work authorization for the foreign worker – Form I-797 - Notice of approval – that will be sent back by the employer to the applicant in order to achieve the work visa application in a U.S. embassy or consulate abroad.
Even if the U.S. authorities approve the application for employment of a foreign national in the country, form I-797 – Notice of approval – does not guarantee the delivery of a work visa. The applicant must indeed go ahead with the work visa application by providing the local American embassy or consulate with: a valid passport, forms DS-156 and DS-157 completed, the original Form I-797 sent by the employer in the U.S., a passport-sized photo, payment of processing fees and a prepaid courier envelope with his/her physical address for passport return. An interview with an immigration officer will then be set up as well as a medical examination. If successful, the applicant will get a work visa.
Each employment category for admission has different requirements, conditions and authorized periods of stay. It is important that you adhere to the terms of your application or petition for admission and visa. Any violation can result in removal or denial of re-entry into the United States. The process can be depend on your category of work you are applying through.