It is important to note that when it comes to proper website etiquette, you must have custom error pages instead of the standard ones, this is because if someone gets a nasty 404 File Not Found error, it may frustrate them and they will never return to your site. Creating custom error documentations can easily help and guide the user back to the site and over to the appropriate page. The best solution is to do it using the htaccess file. Simply add this piece of code to your htaccess document, and you're done.
This technique works best accross all Apache and Linux hostings and is RECOMMENDED
ErrorDocument 404 /error_pages/404.htmlSimply replace the folder named error_pages to whatever you want, and save the 404.html page to whatever file format you see fit.
Another example is to create multiple custom pages for each different error using the same technique mentioned above.
ErrorDocument 401 /error_pages/401.html
ErrorDocument 404 /error_pages/404.html
ErrorDocument 500 /error_pages/500.html