How To Write A Personal Essay For Common App . You are required to write one personal essay for the common app (plus any supplementary essays required by individual schools — more on that later), and the length must be 650 words or less. Discuss an accomplishment, event, or realization that sparked a period of personal growth and a new understanding of yourself or others. Common App Essay Help Table of Contents from foreigncredentials.org Do focus on a single story. The common application, or common app, is a college application portal that is accepted by more than 900 schools. Brainstorming your common app essay topics.