I think we had exercises like that in hs. In ten words or less, describe an event. “Just the facts. Ma’am.” But for an app, with some charm, humility, or whatever will catch the reader.
In fact, boiling down OP’s D’s message to a minimum number of words helps focus on the gist, first.
“I only went to the meal site because my friend needed a ride. It wasn’t that interesting folding utensils into napkins or moving chairs. But with the first scoops of mashed potatoes I served, I could see how important our work was for the people who came for the dinner. I learned this would be the only meal for some, that weekend. They were grateful and I was happy to help. At the end of the shift, I signed up to come back, have been on the team since junior year. I told others about this work. Now there are five friends from my hs who go together.”
Around 100 words. Just off the top of my head but shows willingness to give a friend a ride and try it out. The compassion and personal meaning, humility, the commitment, some recruiting. Adcoms don’t need to know how she got assigned to serve potatoes or whether she also peeled carrots, whether this was in a church basement or how guests dressed. Etc.