1.Create a directory for project on htdoc directory in xampp if you using wamp server then you create your directry on www directory.
2.Open your project directory with command prompt after that write this command:-
composer require mpdf/mpdf
3.After that install phpmailer through composer:
composer require phpmailer/phpmailer
4.Create index.php file and write this code
5.create makepdf.php file and write this code