I still think that you mix up the "green card" and the "H1B visa".
The green card is a status of a permanent resident. A person legally living in the US for enough time (5 years or so) on a variety of visas can apply to get it. It costs significant money so an employer usually helps with that.
The H1B visa is a visa for a worker on a position for which a company fails to hire a worker in the US. That worker may become or not become a permanent US resident afterwards.