If you do not want learners to register themselves for courses you can hide the Catalog tab.

To hide the Catalog tab:

1. Click on “Manage” in the left navigation pane.
2. Click on “My Organization.”
3. Click on “Features” in the left-hand menu.
4. Click the “Catalog” tab.
5. Find the entry for “Display Catalog Tab” and to the right of it, click the “No” button.
6. Click the “Save” button.