Hello Aspirant,

The type of exam should you give depends on the University you're looking for and also the course.

SAT or ACT is basically for Undergraduate courses while GRE and GMAT is for Postgraduate courses. TOEFL and IELTS are basically English Proficiency tests. They are given by the candidates whose native language is not English, it too varies according to the university. Every university has it's different criteria but if you're looking for Undergraduate course then you should give SAT as it is accepted by many universities and the language exam based on what the university is accepting.