Hello Kyrsten and welcome to the Canvas Community! This document should be helpful in accomplishing this,How do I customize my Courses list as a student?, as it shows how you can hide a course from your dashboard and course list. The course is not permanently removed, so if you find that you would like it to appear on your dashboard again, you can favorite it late.
If you drop a course, most institutions will have a system that automatically removes you from the class after the drop is finalized. However, if the course still appears on your dashboard you might contact your Registrar's Office or perhaps even the course instructor to determine how you can be formally removed from the course.
I hope this helps and best wishes!
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