You might use the CloudDB or the FirebaseDB components to create a Chat app. Is that what you want to do Maddu?
Antonio shows you two ways to create a Chat app:
http://kio4.com/appinventor/8CChatfirebaseDB.htm
Here is a third https://opensourceforu.com/2016/11/creating-chat-application-app-inventor-2/
There are other ways (“google” app inventor clouddb or firebasedb chat) or search on the old Google Forum.
Regards,
Steve