Users can log out from their platform by clicking on their name in the top right. In the drop down they can click on Sign Out.
This Advanced, Premium, and Enterprise feature allows you to set the number of minutes that can elapse before a user is logged out for inactivity. Just click on Security & Compliance under Home.
Scroll down until you see this section:
After the specified amount of time has elapsed without any activity from the user, this warning message will be displayed.
If the Continue button is not pressed, the user will be logged out five (5) minutes after the message appears.