Why are 2 php7.0 config files needed?

Question

linux

Hello everyone :)
installed php on ubuntu, and there are 2 php.ini files, the
first one is in this path: /etc/php/7.0/apache2/php.ini
the second one is in this path: /etc/php/7.0/cli/php.ini
all the modules that I tried to connect (PDO, xdebug, etc.) worked, only in this file /etc/php/7.0/cli/php.ini
the question is in which of these files you need to manipulate the modules (that is, connect: ) ) ?
And why do you need 2 different configurations at all?

Answer 1

apache2/php.ini - for web server
cli/php.ini - for command line