$params = array(
    'timeout'     => 30,
    'httpversion' => '1.1',
    'headers'     => array(
        "Api-Appid" => $api_url,
        "Api-Key"   => $api_key
    ),
    'method       => 'PUT'
);

$data = array(
    'objectID'  => 0,
    'id'        => $contact_id,
    'f1564'     => 'https://myfleurdevie.com/checkout/?wpfrc=390'
}

$params['body'] = json_encode( $data );

$response = wp_remote_post( "https://api.ontraport.com/1/objects", $params );