Additional team and channel-related features and issues within Microsoft Teams for Education
Hi Aveek Roy,
Welcome to post your question in our forum.
To sign out of Teams desktop client, simply click on your profile picture on the upper right corner and then you will see the sign out option at the bottom of the small window, see below picture:
Similarly, you can click on your profile picture in the upper right corner and you will see the option to sign out Teams web app.
Hope above information helps. Please feel free to let me know if you have any other problems when using Teams, I'll glad to provide further suggestions.
Best regards,
Jennifer