I want to download the roster as a .csv or .xlxs file.
I don't think you'll be able to download the roster from people but you can get that information by exporting the grade book. Here is a guide that can walk you through that process: How do I export grades in the Gradebook?
Edit: You can use the Canvancements - Canvas Enhancements provided byJames Jones.
You can read more about his Course Roster Enhancements tool!
Retrieving data ...