On Linux, you would find /etc/php or /etc/php74 (if your php version is 7.4) or something like that.
I saw
https://www.edureka.co/community/69677/how-to-find-the-php-ini-file-from-the-command-line for windows.
You can also create a file whatevernameyouwant.php with the content
<?php
phpinfo();
?>
place it somewhere on your website, and point your browser to the page.