All 3 of those schools’ websites CLEARLY spell out requirements and additional info for international applicants. You had better become very familiar with those items rather than relying on internet strangers’ guesses. Below took me fifteen seconds in google. You might also invest some time in the international students forum here on College Confidential
http://admissions.yale.edu/international
https://college.harvard.edu/admissions/application-process/international-applicants
http://admission.stanford.edu/application/international/index.html