Alternative Version
Install PHP Extension
$ sudo apt install php7.3-xml
$ sudo apt install php7.3-mongodb
$ sudo apt-get install php7.3-mysql
https://www.php.net/manual/en/simplexml.installation.php
https://www.inflearn.com/questions/1026746/php-mysql-%EA%B2%8C%EC%8B%9C%ED%8C%90-%EB%A7%8C%EB%93%A4%EA%B8%B0-%EC%8B%A4%EC%8A%B5-%EC%97%90