Nexmo send message using PHP

<?php

/* Nexmo send message using PHP  send-sms-api*/

    $ch = curl_init('https://platform.clickatell.com/messages/http/send?apiKey=xxxxxxxxxxx==&to=xxxxxxxxxxxx&content=hello test message');
    curl_setopt($ch, CURLOPT_POST, true);

    curl_setopt($ch, CURLOPT_POSTFIELDS, $data);


 curl_setopt ($ch, CURLOPT_FOLLOWLOCATION, 1);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
$result = curl_exec($ch);


?>