Is there any facility in b4a for notification of the presence of new email message(s). I know some browsers have this.
For example if you are already logged then you can see a small notification icon on the top right with the number of new messages.
Emails are not handled by the OS. Each email client app handles the mails internally (unlike SMS messages). On new devices you can monitor all the notifications and try to find email notifications: NotificationListener library (NotificationListenerService)