Hey Krishna Reddy,

SAT, ACT, and SAT Subject Tests are all optional, but they will be considered if submitted. for the applicants whom subject tests are required should take Math Level 1 or 2 and a science. You may submit their SAT Subject Testscores as supplemental information to their application

Hi there. 

If you want to study abroad then yes it is compulsory to write the SAT subjects tests. 

Foreign universities and colleges consider srudents for admission based on their SAT scores and TOEFL scores. Other than that if you want any specific information regarding the SAT tests please feel free to post your questions here. 

Hope this helps. 

Good luck!