If you spend 4 years in some American university , what is the next?
Then you have to apply for OPT (Optimum Practicum Training) which allows you to work on F1 visa. If you have STEM major you get 3 years . If you have non STEM major you get 1 year. While you on OPT you apply for H1B. There are only 60,000 slots and 200,000 people apply each year so you have to be lucky because its a lottery system. Then depending on your country it would take 522 years to get green card. It is so because Green card through H1B is based proportionally for each and every country. Meaning it is based equally for both people of India or Bhutan. There aint many applicants from Bhutan or Burundi for that matter so they would get in approximately 5 years . But if youre citizen of these four countries namely India, China, Philippines and Mexico it takes at least 2 decades. Then after you get green card wait for 5 years to get citizenship. Hence if you are STEM major and you came from country who doesnt have that many F1 students in the US you would get citizenship within a decade. But if you are citizen of above mentioned four countries, it would take at least 34 decades.