Hi LexA! 

While Calendly doesn’t have a check-in and check-out feature we do encourage you to use our no-show feature. You can read more about it here → Marking no-shows in Workflows

The other option you have for marking when an invitee arrives and when they leave is in meeting notes. This will require you to navigate to the meetings area and select “Past Meetings.” Once there you can add notes. That metadata will live there forever and be available if ever you need an export. I wish we had a better solution for you but, at the moment, Calendly is primarily a scheduling and calendar management application and not a conference platform. If any of this is murky or you need more information, we are here. Please don’t hesitate with more questions!