A nice example of a "404 - Not Found Page" here
Custom error pages can be created from cPanel -> Advanced -> Error pages.
Once you create them you should create .htaccess file in the public_html directory containing one of the lines below:
For custom 404 error page: ErrorDocument 404 /404.shtml
For custom 500 error page: ErrorDocument 500 /500.shtml
Custom error pages are displayed when a user enters a wrong URL, an outdated URL or when the user is not authorized to access a specific directory of your web space.
400 (Bad Request)
401 (Authorization required)
404 (Wrong page)
500 (Internal server error)
To customize the error page first choose the domain -> choose the error page number (400, 401, 403, 404, 500) or the error page name (Bad Request, Authorization required, etc). When the page loads the following tags can be put into your error page:
Referring URL - Displays the url of the web site the visitor was previously viewing.
Visitor's IP Address - Displays the IP address of the visitor viewing the error page.
Requested URL - Displays the intended url the visitor is trying to view.
Server name - Displays the web site's server name.
Visitor's browser - Displays the visitor's browser type such as IE, FireFox, Netscape, etc.
Redirect Status Code - This displays the type of code in the 300-307 range.
Choose the desired tags and press 'Save' button. Your Error Page is ready.
To learn more about Redirection Status Code, visit WikiPedia web page.