Hi @PatriciaO5,

I'm going to guess the course has an SIS ID, an I correct?  The self-enroll option only shows up if the SIS ID is blank (meaning the course enrollments are not syncing with an SIS at all, which the self-enroll would break in most cases).  I don't know of a way to mix those two things together, but if the SIS ID is not needed, you may be able to just remove it, save that change, then see the self-enroll option appear.

Hope this helps!

-Chris