@SachinD using Alert stage you can able to display popup notifications while the Process is running and that too roles who had subscribed for Alerts by admin on the task bar, and you can't send an email through this stage.
Then if at all you want to send an email after passing through the alert stage, then connect the Outbound link of Alert stage to send email action stage that's it.
I hope i solved your query, if no please let me know.
Thanks & Regards,
Sukesh Kumar.