A 404 page simply indicates to the user that the requested page is "Not Found".
How to create a 404 Page
Begin by creating your 404 page in HTML and CSS.
The 404 page should be designed similar to your other web pages. Name your file 404.html and place it with the other pages in your website file structure.
Include a simple message stating the error, possible reasons for the error, and what the user can do next.
The page you designed should contain a link to navigate the user back to the homepage in addition to the link to home at the logo. Remember, the idea is to keep the user within your website.
Add the 404 page URL to the .htaccess file.
Locate the .htaccess file in the root directory of your server. Open the .htaccess file with a text editor (TextEdit, Smultron, Sublime, etc), and add the following line on any line of code: ErrorDocument 404 http://www.(your site location here)/404.html. This will be the entire URL to the 404 page you created.
Note: Save without appending ".txt" to the end. Don't forget to include the period ahead of the .htaccess file name while you upload.
Test to be sure that it's working properly.
Success can be proven by adding an undefined location in the URL of your website. For example - http:// (your site location here)/xyz will take you to your 404 page. Remember to test your links home.
Check out our 404 page.