How can we create custom job alert in sharepoint ?
Besides what have been presented here, you have also the option of exploring 3rd party solutions to customize alerts in SharePoint. I would recommend EnovaPoint’s JungleBell:Â http://www.enovapoint.com/sharepoint-alerts-reminders/.Â
I haven’t done this but take a look: https://technet.microsoft.com/en-us/library/ee428323.aspx
Why not use designer workflow to send an email with customized  information. Another alternative is create event receiver that sends an email to the user.Â
I am using sharepoint 2013 , Actual requirement is when ever the user register to my site , then he able to receive alert’s via email and sms from Lists.Â