A custom 404 error page lets you display a well-designed page when a page-not-found error occurs. It makes a web application user-friendly and helps the user to navigate back to your website. Without a custom 404-page, an error message appears on the screen when the user clicks on the broken link or nonexistent URL. The visitors may leave your site for page-not-found error, to overcome this problem custom 404 error page gives an opportunity to display a customized message page with homepage redirect link.

There are many reasons for having a 404 page in CodeIgniter. Mainly the broken links are responsible for showing a 404 error page. CodeIgniter displays default 404 page when a 404 error occurred. You can easily customize 404 (Page-not-found) error page as per your needs.