Building, integrating, or customizing apps and workflows within Microsoft Teams using developer tools and APIs
Tabs are Microsoft Teams-aware webpages embedded in Microsoft Teams. They can be added as part of a channel or a group chat inside a team or as a personal app for an individual user.
https://learn.microsoft.com/en-us/learn/modules/embedded-web-experiences/
Also refer: https://www.youtube.com/watch?v=pGAD3pRgZ88
Thanks,
Prasad Das
If the response is helpful, please click "Accept Answer" and upvote it. You can share your feedback via Microsoft Teams Developer Feedback link. Click here to escalate.