If you're working with a small group of participants for a class, course, workshop, or some other regular event, you can use custom fields to track attendance.
Create two multiple choice custom fields and add all participants as choice options.
Label one field Yes (or Present) and the other No (or Absent).
You could also consider creating both options under the same choice field, with YES or NO options for each participant:
This method is only practical for a small group of participants, but can work well for tracking attendance in a scenario where the same small number of people are attending. You can deactivate the custom fields when the course/class is over and you no longer need the attendance tracking on your calendar.