$post = [
'Zoho-oauthtoken' => '1000.f189b94e54fe74192837c3e3df3be21a.10a079e7b1cfb9cdc86cc1dcbd191363',
'client_secret' => '',
'client_id' => '',
];
$ch = curl_init();
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt( $ch, CURLOPT_CUSTOMREQUEST, 'GET' );
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($post));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/x-www-form-urlencoded'));
$response = curl_exec( $ch );
echo '<pre>';
print_r($response);