Yes. Learners accessing the LMS can self-enrol in any publicly available Alison course via their Learner Dashboard. These self-enrolled courses are not assigned by you and are undertaken voluntarily by the learner.
Self-enrolled course activity is visible to you as the Super Admin or Admin in the Self-Enrolled reports tab. Group Managers can see self-enrolled activity for learners within their group.
If you are on LMS+, you can choose to sponsor certificate purchases for self-enrolled courses, but you are not required to do so unless you have agreed to this with the learner.