Obtaining a U.S. green card is a multi-step process. If you are a foreign worker seeking a green card, the first step in the process is normally to obtain a job offer from a U.S. employer. After that, the employer completes a labor certification on your behalf -- which is itself a prerequisite to your applying for a green card.
 
Labor certification, commonly known as PERM, is a multi-step process within itself, as explained here.
 
Labor Certification Step One: PWD Request
As the first step in the PERM process, your employer makes a “prevailing wage request” to the U.S. Department of Labor (DOL) via its website. The prevailing wage request provides the DOL with information about the offer such as job requirements, job duties, and the worksite location. The DOL uses this information to issue the employer a prevailing wage determination (PWD), stating the common wage for the specific job position in the specific worksite location.
 
The PWD is an important aspect of the PERM process, because immigration law requires that employers pay foreign workers at least the prevailing wage for the worker’s position. PWDs can vary greatly based upon the geographic location of the job. For example, the PWD for an attorney working in metropolitan New York is going to be very different from the PWD for an attorney working in rural Texas. Employers must provide the correct worksite location on the prevailing wage request to ensure that the DOL gives the employer the accurate PWD.
 
Labor Certification Step Two: Placing Ads and Recruiting
The next recruitment step is especially critical, as the entire point of the PERM process is to demonstrate to the DOL that no willing and qualified U.S. workers applied for the job opportunity. Your employer must conduct “good faith” recruitment, which means the recruitment must be genuinely calculated to attract any available U.S. workers.
 
For PERM, there are three mandatory advertisements. Your employer must place an advertisement with the state workforce agency in the state of intended employment.
For instance, let’s say your employer is located in Virginia, but the job opportunity is located in Maryland. Your employer must place the advertisement with the Maryland state workforce agency, since that is the area of intended employment.
 
Additionally, your employer must place newspaper advertisements on two different Sundays. The newspaper must be the major newspaper of general circulation in the area of intended employment. In the above example, a good choice for the newspaper would be the Washington Post.
 
Along with the mandatory advertisements, your employer must also place three other advertisements and post a notice of the job opportunity at the worksite location.
 
It is usually recommended that employers place all of the advertisements at the same time (or close to the same time) if possible. The reason for this is that all of the advertisements must be less than 180 days old at the time of filing the PERM application. If one of the advertisements is older than 180 days, that ad cannot be used for the PERM, and the employer will need to place another ad before filing the PERM.
 
Labor Certification Step Three: Filing ETA Form 9089
After the advertisements are complete, your employer will file the PERM application with the DOL using ETA Form 9089 (provided no qualified and willing U.S. workers applied for the job position). Just like with the prevailing wage request, your employer files this form electronically at the DOL website. The ETA Form 9089 again provides the DOL with information on the job opportunity (such as the worksite location, duties, requirements, and prevailing wage), information on the employer’s recruitment process (such as where the employer placed the ads and on what dates), and information on the foreign worker (such as the worker’s place of birth, education credentials, and work experience).
 
After filing the ETA Form 9089, you will wait several months for the DOL to adjudicate the PERM. The DOL can (1) approve the PERM (2) deny the PERM or (3) audit the PERM. If your PERM is audited, the DOL will ask your employer to provide additional evidence for the application. After your employer responds to the audit request, the DOL will review the new evidence and either approve or deny the PERM.
 
After receiving the approved PERM, your employer can move on to the next big step of the process, which is filing an I-140 visa petition on your behalf with U.S. Citizenship and  Immigration Services.