curl call in php with authorization headers

<?php
$apiUrl = "URL";

$fields = json_encode(array());



$ch = curl_init();

curl_setopt($ch, CURLOPT_URL, $apiUrl);
curl_setopt($ch, CURLOPT_HTTPHEADER, ['Authorization: 1000.8c06876128ca17e14e5d0afcc6ffaa28.f73b0347b0c4b42b041f7c3cb5dea3d8']);
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "GET");
curl_setopt($ch, CURLOPT_POSTFIELDS, $fields);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 60);
curl_setopt($ch, CURLOPT_TIMEOUT, 60);
/*CURLOPT_HTTPHEADER => array(
    "cache-control: no-cache",
    "content-type: application/x-www-form-urlencoded",
    "ownerkey: 66389a72fe00776ef42ec16c4e9874e5",
    "postman-token: ddcb7396-6e01-cd8a-b588-a16c061d51f9"
),*/
$result = curl_exec($ch);
echo $result;
curl_close($ch);
?>