By default, all Courses in Moodle are accessible only by registered user or registered students. Sometimes we want the course to be available for public so that non-registered user can also view the course. To make it public follow the steps below...

1. Create new Course
2. Go to the newly created Course
3. Go to Administrator > Course administration > Users > Enrolment methods and enable public view in 'Guest access' by clicking eye icon open.
   
4. Go to Administrator > Course administration > Users > Enrolment methods > Guest access and make 'Allow guest access' as Yes (Do not enter password)
   
5. Now, go to Administration > Site administration > Users > Permissions > User policies and tick 'Auto-login guests'
   
6. Now your Course will be available for public access

For More visit
https://docs.moodle.org/29/en/Guest_access
https://docs.moodle.org/29/en/Guest_access#Auto-login_guests