Customizing Your 404 Page Not Found

@replace {{title}}, {{text}}

// Set a custom title for the 404 page
add_filter( 'generate_404_title', function ( $title ) {
   return '{{title}}';
} );

// Set custom text for the 404 page
add_filter( 'generate_404_text', function ( $text ) {
   return '{{text}}';
} );

// Hide the search form from content area on the 404 page
add_filter( 'get_search_form', function ( $form ) {

   if ( is_404() && did_action( 'generate_after_entry_header' ) && ! did_action( 'generate_after_content' ) )
      return '';

   return $form;

} );

#