Additional Information section on Common App?

So I have an extracurricular that is very, very important and I can’t fit everything about it in the Activities section of the Common App. I’d like to explain it in the Additional Information section, but I’m not sure how to do it. Should I put a resume-style description of it (I have made a resume-style description that is about 500 words)? I’m afraid that this would be too long… but I also honestly think that I can’t fit everything that should be said about it in a few sentences/short paragraph. Any advice?

It’s fine to use the additional info section to clarify a unique EC, but you should really try to present it in a clear and concise way, like a few bullet points. 500 words seems like a lot to explain an activity. Admissions officers have enough to read as it is.

If you are comfortable sharing what the activity is, people here may be able to help you with structuring it.

^Agree. My son had an EC that was particularly meaningful, and he elaborated on it in the ‘Additional Info’ section with maybe ~150 word paragraph. Important to be concise. You should be able to relate the importance of this EC without providing every detail.

500 words is not “resume-style”. A resume is purposely short, 1-2 pages max. Professionals with 10, 20, 30 years of experience have 1-2 page resumes with less than 500 words.