I’m not sure what happens at your high school, but my kid’s transcripts listed classes, grades and GPA – and nothing else. Their transcripts did not list community service or extracurricular activities, so college admissions has no way of knowing what a student has done outside of the classroom unless the student (or teacher and guidance counselor in their recommendation letters) tells them.
Many student’s, like yourself, assume there is a section on the Common Application that asks about community service, but there isn’t. If students have done community service – and many haven’t – they list it under extracurricular activities, and are supposed to list those activities in the order of importance to them.