I created a SharePoint 2013 type workflow (using SharePoint 2016) in SharePoint Designer. When a task is assigned then user is receiving two emails. One email is my custom email which I have set in workflow and other is system generated. The other email seems like the one which is sent by SharePoint when you are subscribed to Alerts on a list. But the thing is I haven't done any subscription so why users are receiving this email and how to make it stop?
Screenshot given below: