How to create your own email content for all the alerts emails which are sent OOTB . I need to modify the email content of all the alerts send OOTB (The immediate emails, update email , delete email , daily summary alert email and weekly summary alert ) . I know of creating copy of alerttemplate.xml and editing it but how to ensure all email alerts content are modified .
This is already answered here SharePoint 2013 email templates
and here a good blog post on this