rpress_order_note_meta

This filter is applied to use the order note metadata, it is one parameter.
$order_note -> get note details.

An example of how you can append additional information:

function rpress_order_note_fields( $order_note ) {
$order_note = isset( $_POST['rpress_order_note'] ) ? sanitize_text_field( $_POST['rpress_order_note'] ) : '';
return $order_note;
}
add_filter( 'rpress_order_note_meta', 'rpress_order_note_fields' );