<?php 
require_once( '/var/www/html/corepla/wp-load.php' ); 

$the_query = new WP_Query( ['posts_per_page' => -1]);

if ( $the_query->have_posts() ) {
$i=0;
    while ( $the_query->have_posts() ) {
	$i++;
	echo $i . "\n";
        $the_query->the_post();
        $id = get_the_ID();
	$contenuto = get_field("elementi_editoriali_scuola", $id);
	//echo $id . var_dump($contenuto) . "\n";
  $my_post = array(
      'ID'           => $id,
      'post_content' => $contenuto
  );

// Update the post into the database
  wp_update_post( $my_post );

        // All Post Data Available Now
        // Do what you want with it
    }
}

?>