如何更改mPDF输出（）的根文件夹？

How can I change the root folder of my mPDF Output()?

I need a filename that is taken from a variable and the file should be saved in my folder called "/files". The location for the file should be in a variable like $location =("/location").

Now my output is generating in the root folder.

$sql=mysql_query("SELECT * FROM `client_details` ORDER BY `c_id` DESC LIMIT 1");  

while($data = mysql_fetch_array($sql))   
{ 
    $name=$data['name'];
}

$name_p = $name."-estimation.pdf";
$mpdf->Output($name_p,'F');

$mpdf->Output("/absolute/path/to/directory/" . $name_p,'F');

or

$mpdf->Output("relative/path/to/directory/" . $name_p,'F');

$path = __DIR__.'/../../files/'; //til you're at the location of upload 
/*
//you can use, will return false if incorrect path
die(realpath($path to make sure you are at the right level))
*/
//concatenate file path to your file name 
$mpdf->Output($path.$name_p,'F');