Fatal error: Class 'Document' not found in C:\xampp\htdocs\test.php:4 Stack trace: #0 {main} thrown in C:\xampp\htdocs\test.php on line 4

Question

I want to make test.php can convert input1.pdf become docx file, but igot this error

Fatal error: Class 'Document' not found in C:\xampp\htdocs\test.php:4 Stack trace: #0 {main} thrown in C:\xampp\htdocs\test.php on line 4

test.php full code

<?php

# Open the target document
$pdf = new Document($dataDir . 'input1.pdf');

# Save the concatenated output file (the target document)
$pdf->save($dataDir . "output.docx");

print "Document has been converted successfully";

?>

may somone help me? thanks