Warning: require_once(vendor/autoload.php): failed to open stream: No such file or directory in C:\xampp\htdocs\phpmailer\test\bootstrap.php on line 2

Fatal error: require_once(): Failed opening required 'vendor/autoload.php' (include_path='.;C:\xampp\php\PEAR') in C:\xampp\htdocs\phpmailer\test\bootstrap.php on line 2