How do I get the latest note on the order at woocommerce? [closed]

The order notes are saved as post comments, so you can use the WordPress function get_comments() to get the last note:

$args = array(
    'post_id' => $order_id,
    'orderby' => 'comment_ID',
    'order'   => 'DESC',
    'approve' => 'approve',
    'type'    => 'order_note',
    'number'  => 1
);

remove_filter( 'comments_clauses', array( 'WC_Comments', 'exclude_order_comments' ), 10, 1 );

$notes = get_comments( $args );

add_filter( 'comments_clauses', array( 'WC_Comments', 'exclude_order_comments' ), 10, 1 );

By default Woocommerce excludes order notes when calling the get_comments function. To prevent this, you have to remove the filter, call get_comments() and add the filter again. I copied this code from the function WC_Meta_Box_Order_Notes::output() in wp-content/plugins/woocommerce/includes/admin/meta-boxes/class-wc-meta-box-order-notes.php and added “number”, so you just get the last note.