Warning: require_once(vendor/autoload.php): Failed to open stream: No such file or directory in /var/www/html/generate_pdf.php on line 4

Fatal error: Uncaught Error: Failed opening required 'vendor/autoload.php' (include_path='.:/usr/share/php') in /var/www/html/generate_pdf.php:4 Stack trace: #0 {main} thrown in /var/www/html/generate_pdf.php on line 4