When you apply to college you are competing for admission against other students who typically have similar grades and test scores to you. One of the factors that colleges consider in deciding who to accept are your volunteer activities.
Why do colleges care about whether you volunteer? Colleges like to see students who care about something other than themselves. You might have good grades but if you don’t care about anyone other than yourself, you are not the type of person that colleges really want.
Can you get admitted without having done any volunteer activity? Of course. But the more competitive colleges have little incentive to accept someone who doesn’t try to make this a better world.
Now, don’t misunderstand, you can’t be a super volunteer and ignore your grades. Grades and test scores will always trump volunteering. However, all things being equal, colleges will prefer the student who has spent time volunteering.
Volunteering can also pay off. One of my students last year was not only a strong student but also a super volunteer. She received several full ride scholarships to very competitive colleges related to her volunteer activities.
What are you going to do to improve the world?