What is an H1B visa?

In simple words, an H1B visa is a non-immigrant, employment-based visa for temporary workers. For this visa, an applicant should offer a job in the US, and the employer should file a visa petition on behalf of the applicant with the US Immigration Department. This approved visa petition is a work permit that allows the applicant to get a visa stamp and work in the US for that employer. This visa is generally issued for special occupations that require practical and theoretical specialised knowledge and require the visa holder to have at least a Bachelor's degree.

An H1B visa is a non-immigrant visa that is known as a labour visa. The American company uses this visa to hire workers outside the country for a short term to fill the labour force. However, if the companies find any of those employees more valuable to the company in the long term, they can apply for the US green cards, thus allowing the status change of those employees from non-immigrant to migrant status. Additionally, this visa comes with a term limit. After the completion of this visa, the employer can either return to his/her home country or the company for which he/she is working can apply for their visa renewal.

As per my understanding, it is a work visa for applicants who have specialized knowledge in any specific field, such as finance, engineering, science, accounting, IT, architecture, mathematics, etc., that fulfills the demands of the US companies. The prospective employer files the visa application for the employee and allows the employee to work for their company only till the visa validity.