ob_end_clean();

$dompdf->stream();

    <?php
        require 'vendor/autoload.php';

        // reference the Dompdf namespace
        use Dompdf\Dompdf;

        $content = '<h1>Hello World</h1>';

        // instantiate and use the dompdf class
        $dompdf = new Dompdf();
        $dompdf->loadHtml($content);

        // (Optional) Setup the paper size and orientation
        $dompdf->setPaper('A4', 'landscape');

        // Render the HTML as PDF
        $dompdf->render();

        ob_end_clean();

        // Output the generated PDF to Browser
        $dompdf->stream();
    ?>