A foreign national can obtain a green card based on a permanent employment offer in the United States. Some of the employment based visas require the previous approval of a Labor Certification.

The employment based categories are:
Employment First Preference – Priority Workers: This category includes persons with extraordinary ability in the sciences, arts, education, business, or athletics; outstanding professors and researchers with at least three years of experience in teaching or research; and multinational manager or executives.A Labor Certification is not required.

Employment Second Preference  : This preference includes professionals holding an advanced degree and persons of exceptional ability. A Labor Certification is generally required, unless the applicant applies under the National Interest Waiver exception.

Employment Third Preference  : This preference includes skilled workers, professionals, and unskilled workers.Generally, a Labor Certification is required.

Employment Fourth Preference :  Special Immigrants, including religious workers, employees of United States foreign-service posts, retired employees of international organizations, among others, can apply under this preference. A Labor Certification is not required.

Employment Fifth Preference  : foreign investors who invest $1 million or $500,000 (under certain conditions) in a new commercial enterprise in the United States that employs at least 10 full-time workers can qualify under this preference.