Hello ​@Linda_charlton,

You can add a new course now. But only respondents who start the survey after the changes are published will see the updated version. Those who have already started the survey will not see the new course.

If it’s about already completed responses, you can ask them to retake the survey and send them the retake link. 
If you can’t ask for retake then you can change response in Data & Analysis tab. But this is not recommended.

The Question Was for Course Evaluation setup where you uploaded all the courses.

Hello ​@Linda_charlton,

As per my knowledge you can edit the courses. Just upload the details back with new course added in it.

Still I would suggest you to check with Qualtrics support once or you can test with dummy data once and if no issues then go with real data.

I fixed the problem by creating a new evaluation with just that course that was missed since I needed the evaluation fixed by now.