Sometimes, you will want to control the access to your courses so you will have to make them Private.
In order to so, Edit the Course clicking on the pencil icon.
Scroll down on the information page of the course and tick the box to make it Private.
Once you tick this box, the URL to share with your Learners will appear.
You can also add Learners to a course manually.
Please read the support article on Adding Learners.