If the company I am working with offered me a future employee green card, I would like to know is it doable? How does this work?

I would like to ask a question about the future employee green card. There is different process of green card. I am a student and I am on F1 visa and working with company "A" on "CPT" as a part time. As per the normal process, once I complete my studies I can work on OPT (then look for H1B) H1B (look for green card). And is it better than the above process? These questions arise in mind as it directly gives an option for green card. Please help me to understand this process in a better way.