Sharepoint 2013 - Modify new Alert notification message

Question

Our site owners will signup alerts for other users in the site for document library and discussions.
An email will go out to users when we signup alerts and want to modify that alert/email template. 
Which email alert template below email refer to, want to modify email message to remove '<System Account>' and add additional static text.
Email Received:
Subject: An alert for 'Team Discussions' has been created
Body: 
'<System Account>' has subscribed you for alert 'Team Discussions' on '<Site Name>'. 
You will receive alerts according to the delivery method, timing and criteria that were selected when the alert was created.
You can change this alert or any of your other alerts on the <My Alerts on this Site> page.
Regards,
-RK
Thanks

Answer 1

According  to your description, you want to customize the default format of alert mails.
For  implementing your requirement, you are able to modify an XML file called alerttemplates.xml located in C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\XML. 
Here are some links for your reference:
Modify the appearance and email body of alerts
http://jimecox.wordpress.com/2012/01/29/modifying-the-appearance-and-email-body-of-alerts/
How to customize SharePoint Alert Email Template
http://www.alectang.com/blog/archive/2012/05/16/how-to-customise-sharepoint-alert-email-template.aspx
http://community.bamboosolutions.com/blogs/bambooteamblog/archive/2012/08/21/how-to-customize-the-discussion-board-plus-email-alerts-for-sharepoint-2010.aspx
Though,
this is your requirement, but personally I want to suggest you not to do it as because this alert configuration is FARM specific which will Add those lines for ALL WEB APP / SITE COLLECTION / LIST / LIBRARY alert email. Hope this will help
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