How to required autoload.php for phpmailer

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Windows

PHP

I was trying this function but not included the file in laravel.
showing error

failed to open stream: No such file or directory 

I am working on laravel !

What I have tried:

require 'vendor/autoload.php'
    and
include_once(app_path() . '/vendor/autoload.php');
    and
require base_path().'\vendor\autoload.php';