There are a couple of ways in which you can immigrate based on a job offer. For example, you may be allowed to become a permanent resident of the US if you are employed in the states. A lot of categories require you to have an employer that has a certificate of labour. On top of this, they will also need to file an I-140 on your behalf. You can also get a green card through an investment, so if you are an entrepreneur and you want to create an enterprise that will in turn into new jobs for US citizens, you can do so while getting permanent residency at the same time.
Another way to get a green card would be through a self petition. Some categories allow you to file a petition for yourself and you can get this if you have an extraordinary ability or if you have a national waiver.
If you don't qualify for any of these then you will be glad to know that you can also obtain a green card by taking part in a specialist job or position. Some of these include a Panama canal employee, a religious worker, a broadcaster or an Iraqi translator.
It should be noted that some of these positions require more documentation when compared to others, and that it may be a good idea to contact your visa professional before you apply for a position to make sure that it is the right one for you.
In some instances, you may not be eligible for any of these but that doesn't mean that you can't get a green card at all, there are plenty of other ways in which you can obtain one and some of them are easier when compared to others.