To create your custom php.ini, you just need to follow these steps:

1. Create a file named ".user.ini" (without quotes)
2. Place your new .user.ini file in the wwwroot of your application (example: E:\HostingSpaces\Username\www.yourdomain.com\wwwroot\.user.ini) This can be done either through your File Manager in your WebsitePanel or through FTP.
3. Add PHP directives to your new .user.ini file such as:
memory_limit = 600M;
upload_max_filesize = 1000M;

4. Recycle your website's application pool.

The values you configure in this document will override the master values set in your PHP instance's global php.ini file, the same way it does on Linux.
The next part is testing our change:

1. Create a phpinfo.php file in your wwwroot root (Example: E:\HostingSpaces\Username\www.yourdomain.com\wwwroot\phpinfo.php)
2. Add the following line to your phpinfo.php file:

<?php phpinfo(); ?>

3. Save phpinfo.php
4. Visit http://www.yourdomain.com/phpinfo.php in your browser.
5. If done followed the steps above correctly, you should now see the new, modified value(s) in the first column, like this: