You should get into the habit of logging out when you have finished your session - here's how

Logging out from the start screen

To log off when on the main start screen, click the logout button, top left

Logging out from other screens

Most of the screens in Flow360 also have a logout button near the bottom of the lefthand side bar. Simply click to immediately end your session and logout.

Direct log out from the new Helpdesk issue screen

When you log a new Helpdesk issue you have the option of saving the issue and logging out all in one go by using the Confirm & Logout button, top right.