Can I repeat information in a secondary essay that is already covered in my primary application?

Yes. However, this is your opportunity to expand on what you have already written about in your primary application. For example, if the question is asking you to describe your volunteer experiences, do not just copy and paste what you wrote on your “Works and Activities” section. Rather describe your experience but also expand on why it was important and how it impacted you as a person. This is your opportunity to show your motivation and interests.