The first thing to know : It is very, very different from what we are used to in Malaysia.
A medical school in the United States is a four-year graduate institution with the purpose of educating physicians in the field of medicine. Such schools provide a major part of the medical education in the United States. Graduates receive either a Doctor of Medicine (M.D.) or a Doctor of Osteopathic Medicine (D.O.) degree.
Admissions to medical school in the United States is generally considered competitive. Admissions criteria include grade point averages, Medical College Admission Test scores, letters of recommendation, and interviews. Most students have at least a bachelor’s degree, usually in a biologic science, and some students have advanced degrees, such as a master’s degree. Most students that apply to medical school do not matriculate at a medical school. Medical School in the United States does not require a degree in biological sciences. People with degrees in different fields can be admitted to medical school as long as the criteria for admission is followed.
In short, in the USA, AFTER you complete your undergraduate degree, you will undergo medical school. It means 4 + 4 = 8 years, unlike in Malaysia.