I am not sure I understand the question. An immigrant is a person who leaves one country to permanently reside in another. If it is a legal move, than most likely the individual is a permanent resident and therefore treated as an American citizen basically having the same rights and privileges. So, just apply to a college or university like anyone else.
Now if you are referring to the status of a Foreign Student (F1 Visa), then contact a college or university or your choice and ask to speak with the Foreign Student Adviser. He/she will direct you appropriately so that you can secure the form I-20 which you need to submit to the US Immigration and Naturalization Service (if you are already within the US on another Visa type), or to the American Embassy located in the country you now reside in.
A lawful immigrant who has become a naturalized American Citizen can become a police officer, but not an immigrant/alien who has not become a US citizen.
it depends whether the immigrant has committed felonies
Check with the laws in your state before getting married, but in most states, anyone who marries a United States citizen can become a US citizen, and thus be legal.
No.
yes a immigrant can become a citizen
No.
Yes this is very common
No
No.
Yes. If the illegal immigrant marries a citizen, they can become a citizen from that.
You become a student by making an effort to learn -- you don't even have to be in school to be a student.
no