Hi @de16,
If you see a "drop this course" button on your course page you could click that. In most academic course situations though, course enrollments are handled by your school and you'd need to contact the registration department (or similar) to be dropped from a course. Your school's Canvas team (usually in the eLearning / IT / Digital Education areas) may also be able to help with this, but in many cases they'd probably redirect you to the registration area.
Hope this helps!
-Chris
