How to edit 404 content via wp editor?

Found a way.

  • Create a regular page for 404 content, say ‘Page not found’;

  • In your 404.php file, get that page data and then write down your content or whatever…

For example:

$page = get_page_by_title("Page not found");  
if($page) echo apply_filters('the_content',$page->post_content);

Obviously, you can do a lot more…