It is US Department of labor certification, which states whether a position at a particular company is available. This is the initial step to receiving a green card.
Why do employers need labor certification?
A labor certification is essential for getting Green Card through employment. A labor certification requires an American employer to demonstrate that there are no qualified or minimally qualified workers in the country to perform the job for which the individual in question is getting hired.
American employers must attest to how many people are available in the country to perform the job the applicant is going to do and also outline the effect the immigrant employee’s employment will have on the working conditions and wages of those working in similar positions in the country.