Interview requirements differ from school to school. Many colleges and universities offer applicants the opportunity to interview on campus with a member of the admissions team, or locally with an alumnus who has been trained to do so, but these interviews are often optional or encouraged rather than required. However, given the chance, I recommend that you interview whether it's required or not.
A college interview is another opportunity to make an impression on the admissions committee, especially if you're able to interview with a staff member on campus. Doing so gives you the chance to share what you can uniquely bring to their campus. But a college interview isn't just a chance to impress your prospective school— it's also a chance for them to impress you.