International students are eligible to take the MCAT so long as you have a valid government issued ID (passport from your home country w/ photo; or US government ID w/ photo)
https://www.aamc.org/students/download/428112/data/registrationtips.pdf
As IWBB said the issue will be – a) getting an acceptance and b) financing your medical education
https://www.aamc.org/students/aspiring/303912/applyasaninternationalapplicant.html