What is the best way to fill out our ECs in the common app? We only have the option to put in volunteer work, academic credit, or compensated work in the “experiences” tab, and about half my ECs aren’t any of those (sports, organizations, internships). I talked to common app and they said to directly inform each school about our other ECs, but that seems extremely inconvenient. Is there actually no easier way to do this? 
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Experiences? ECs go under Activities. There are about 30 activity types to pick from.
There is an option for other activities, you could put it under it.