Visa descriptions and qualifications

H-1B (profession)
An H-1B visa is required if you are coming to the US to provide services in a pre-arranged profession. To qualify, you must have a bachelor's degree or higher (or equivalent) in the subject for which you are looking for employment. USCIS checks whether your employment is a special profession and whether you are qualified to provide the services. Your employer must apply to the Ministry of Labor for working conditions regarding the terms of his employment contract with you.
H-1B1 Contracted Temporary Visa
Free trade agreements with Chile and Singapore allow qualified Chilean and Singaporean citizens to temporarily work in the United States under certain circumstances. Only Chilean and Singaporean citizens are eligible as main applicants, although their spouses and children may be nationals of other countries.
Applicants for H-1B1 visas should already have a job offer from an employer in their chosen field of work in the United States, but the employer does not have to submit Form I-129, Petition for Nonimmigrant Worker, and the applicant does not have to do this before Submit your visa application, Form I-797. However, the petitioner must apply for a foreign certificate before applying for a visa at the Ministry of Labor. Further information on the H-1B1 visa can be found on this page.
H-2A (seasonal workers in agriculture)
With an H-2A visa, US employers can enter foreign nationals to fill temporary agricultural jobs for which US workers are unavailable. An H-2A non-migrant rating applies to you if you want to provide agricultural workers or services temporarily or seasonally in the United States. A US employer (or an association of US agricultural producers that has been designated as a co-employer) must submit Form I-129 (Petition for Nonimmigrant Worker) on your behalf.
H-2B visa (qualified and unskilled workers)
This visa is required if you are coming to the US to do temporary or seasonal work that is short of US workers. Your employer must receive a Department of Labor certification that confirms that there are no qualified US workers who are eligible for the type of employment on which your petition is based.
H-3 (trainee)
An H-3 visa is required if you are coming to the US for a period of up to two years to receive training from an employer in a field or undertaking other than academic education or training. You can be paid for your training, and "hands-on" work is allowed. Training cannot be used to create productive employment and is not available in your home country.
H-4 (dependent)
If you are the primary holder of a valid H visa, your spouse or unmarried children (under the age of 21) may be given an H-4 visa to accompany you to the United States. However, your spouse / children are not permitted to work in the United States.
L-1 (intra-group acquirer)
An L-1 visa is required if you are an employee of an international company that temporarily transports you to a branch, affiliate, or subsidiary of the same company in the United States. The international company can be either a U.S. or a foreign organization. To qualify for an L-1 visa, you must be at the management or executive level, or have specific knowledge, and be intended for a position within the US company at one of these levels, although not necessarily the same Hold position as before. In addition, you must have worked for the international company outside of the U.S. for one year at a time within three years of applying for approval in the U.S. You can only apply for an L-1 visa after your U.S. company or an affiliate has received an approved application from USCIS, either as a flat rate or individually.
L-2 (dependent)
If you are the primary holder of a valid L visa, your spouse or unmarried children (under 21) can obtain this derived visa. Due to a recent change in the law, your spouse can apply for a work permit. Your spouse must travel to the United States on his own L-2 Visa and then fill out Form I-765 (available from USC