The Common Application covers several areas: personal data, educational data, standardized test information, family information, academic honors, extracurricular activities, work experience, a short answer essay, a personal essay, and criminal history. Financial aid information needs to be handled on the FAFSA.
In most cases, the Common Application is submitted electronically, and the Common Application website does a great job organizing your documents and keeping track of the different application components.
Many schools will ask for a supplemental essay to complement the personal essay options provided on the Common Application. These supplements are often submitted through the Common Application website.