Hii

The SAT exam has most of the questions in MCQs form only, and essay is obviously subjective.
It consists two major sections as follows- 
Evidence based reading and writing: Here both reading and writng section are multiple choice question based and you have to choose the correct answer.
Maths Section- Here you have 2 sets of questions. One is to be solved with calculator and the other is done without calculator.  Most of the questions of maths section are MCQs but a few questions are to be solved.
The exam is 3 hours long and if you choose the essay question also then your get extra 50 minutes for essay question.
The score ranges from 400 to 1600  and there is no negative marking done

For Ivy League schools, be informed class 10th marks are not considered. You must score good in class 11th and 12th and also keep a high target in SAT i.e around 1500 and above is a safe score.

Hope this helps. Incase of doubt feel free to revert back
Thanks!!