i have one more question. i am not going in students visa. im going with my parents in immigrant visa. so is it necessary to write SAT or TOEFL? Is it just for international students?

You will very much be required to take the SAT. TOEFL, i cannot really say so as the universities would give you a waiver on the basis of your immigrant visa. Hope my answer has solved your query. If it has, kindly mark it as best answer.

Admission standards have nothing to do with your visa. Hence American students have to take the SAT as well.