any idea, helps suggestions 
Well what things do you do outside of class?
@OrchidBloom i didn’t do anything to put on my extra activity for sure
It sounds like you’ve already made up your mind that there is nothing you can put on there, so why ask for help? If you want people to help, you need to tell us the things you do. Maybe we can help you frame it in a way that works on the Common App. Also, we may be able to make suggestions on what you could now that might interest you and would be a good thing to put on the common app.
What year are you? In other words, how much time to you have to get involved with something? Most colleges like to see some depth, not just “I joined this because I want to look good”, however, doing something now is better than not at all. You have a whole summer to get involved with something.
Do you play an instrument? Sport? Do you have a hobby? What do you do for fun? Do you have a job? Involved in any clubs, organizations? How about at church? Do you volunteer anywhere?
Or you can just apply to schools that admit strictly by GPA and test scores (non-Common App schools). Actually, many of the less selective schools that use the Common App care about ECs only in borderline cases. If your grades and scores are high enough, and your essays decent, you’ll be likely to be admitted even with no ECs.
Do you go to church/synagogue? Do you do any activities besides attend?
Do you babysit your family or others?
Do you do any sports in or out of school?
Do you have a job?
Do you help tutor anyone?
Do you help out in your community?
Tell us how you spend your days. Have you just gone to school, come home, and do homework / watch TV, all day, every day, for the past three years? If you have, why? Maybe there are plausible circumstances that would prevent you from being able to do many activities.You are also allowed to put down extracurriculars that you’ve done and stopped as well.
Also, use this summer effectively! Do some community service, get a job, or learn a new skill.
If you have wasted three years of HS without pursuing anything outside of academics, it does not look good. Take what the above posters said to heart and use this summer effectively.
Do you have a time-consuming (even if not glamorous) job? Do you play competitive MMPORG’s? Are you in charge of sibling, of an elderly relative? Do you live in a place that’s very isolated? Are you homeschooled and kept far from others/activities? Do you cook? Fix things (cars, electronics)? Did you teach yourself something (with or without help from a computer/website)?
We can’t help you if you go home right after school every day and watch tv and do homework. But if you do anything else, it could be considered an EC. You can count things you do in school as well as outside of the school. Paying jobs and unpaid volunteering all count as activities.