This accurate response from @nwilson7 earlier this month to another inquirer might help................
"Hello Christian Catajay, you do not specify if you are a student or instructor so I will provide you both answers. If you are a student, you get the join code from either your institution or the instructor of the course. As the instructor, you get it by going into the course settings, scroll all the way to the bottom and select "more options" in blue and then it is at the bottom of that."
The screenshot below is from one of my open enrollment courses, and shows placement for instructors on the Settings page. The actual "Join Code" (87NXB8) is embedded in a URL that takes recipients to the course.
As a student, you would likely be sent that URL in an email, or would access it from a web page. Depending on the enrollment status set for the course, you will also most likely need to be enrolled in that institution's Canvas account for that Join Code to enable enrollment into the actual course.
If you are a teacher, this guide will help you set up your course for this How do I enable course self-enrollment with a join code or secret URL?
If you are a student, and were not provided the URL, then you need to contact the course instructor.
I hope that this is helpful,
Kelley
