Error while using Dompdf

Question

I am using dompdf to generate pdf and returns this ERROR:

Fatal error: Uncaught Error: Call to Undefined Function Dompdf mb_internal_encoding() in C: Users adnas logisticapratica logisticapratica php pdf dompdf src Dompdf.php on line 274

Code:

<?php
  use Dompdf\Dompdf;
  require_once 'dompdf/autoload.inc.php';

  $dompdf = new DOMPDF();

  $dompdf->load_html('<h1>gerar pdf</h1>');

  $dompdf->render();
  $dompdf->stream(
    'teste.pdf',
    array(
      "Attachment" => false
    )
  );
?>;