You can check this on the Web Browser version.
*The "Last access" timestamp is updated whenever a user performs any operation that involves communication with Teachme Biz (viewing, creating/editing, settings, etc.), regardless of which application is used.
Checking last access for each user
You can check this in the group user list and on the user's profile screen.
Related: Check Users in Group (Web Browser)
https://teachme.jp/8/manuals/39622380/
*Only group administrators and sub-administrators can check the "Last access" on the user's profile screen.
You can also export the list for review.
Related: Export user usage details (Web Browser)
https://teachme.jp/8/manuals/9040403/
Checking last access for each device used by a user
From the user's "Device Used" section, you can check the last access date and time for each device/app they are using to access Teachme Biz.
Related: Temporarily Suspending or Deleting Access from Any Device (Web Browser)
https://teachme.jp/8/manuals/41165858