windows-server-2012如何支持运行“.phtml”文件

I am setting the windows server 2012 with the phtml, however, the server only support ".php" but not support the ".phtml" .

After I run the web-platform to install the php7, The system can run the helloworld.php and it can display the result. But when I created the index.phtml, and run visit the page, the browser would only download the new file, not open the website on the browser. Would I need to add the ".phtml" extension on the IIS? Where I can add the extension?

would I need to add the apache server to support running the ".phtml" Or the IIS can add the extension type like "AddType application/x-httpd-php .php .phtml"

both the index.php and the index.phtml only have the following code