Most American universities and colleges have early deadlines. You must write to American universities a year before you plan to begin your studies and obtain application forms.
Many schools have later deadlines.
To go to a language school, you must write three months before you plan to begin your studies. American universities and colleges will require you to fill their application forms and send it to them with the application fee before the deadline. If your English is not excellent, you will not be able to pass these tests. You will not be able to begin your studies at an American University or college unless your English is excellent, or at least very good. If your English is not sufficient, you will first have to go to a language school.