Hello Olumide Kenny Olamigoke !

1) please specify. It looks like you ant to have a link that calls the email client. If yes, then you may create the link with mailto beginning.

2) Shoutbox block is the part of Jot Messenger which requires installed Jot server.

3) If you mean the Rocket.chat the you may find some info in the app itself (Studio->Rocket.chat->Information) or here, for Cloud variant