Teams Attendance Report
If you've organized a Teams meeting, you can save a record of who's attended it. Here's how:
During the meeting, select Show participants and choose Download attendee list 
.
The report will download as a .CSV file that can be opened in Excel. The .CSV file contains the name, join time, and leave time of all meeting attendees.
Notes:
Keep in mind that, for now, the report must be downloaded during the meeting.
Only meeting organizers can download attendance reports. This option isn't available to other attendees.