Attendance tracking for meetings is turned on by default. Google Workspace Admins currently won't be able to turn off this feature for their domains.
After a video call with at least 5 participants, the meeting organizer will receive an email with an attached attendance CSV report with the following info:
Important: Only G Suite Enterprise for Education moderators can currently receive attendance reports in Google Meet.
Tip: Meeting organizers will get attendance reports for all meetings, including those started from Classroom or meet.google.com.