As there are multiple versions of PHP with different sever configurations, php.ini could be located in several different folders.
You can use php function
phpinfo() or linux command
php -i | grep "Loaded Configuration File" to find out exactly which
php.ini file your web sever is using .
In Linux, there are 3 locations which are common used. Take php 7.2 for example.
/etc/php/7.2/apache2/php.ini is for the PHP plugin used by Apache. This is the one you need to edit if you are using the Apache web server.
/etc/php/7.2/cli/php.ini is for the CLI PHP program. Changes to this config file will only affect PHP as it runs in the terminal – it will NOT affect the web server.
Nginx or Apache with PHP-FPM
/etc/php/7.2/fpm/php.ini is a fastcgi-compatible ‘wrapper’ for PHP processing. This is the one you need to edit if you’re using the Nginx web server or Apache with PHP-FPM.
For versions of Ubuntu lower than 16.04,
/etc/php/7.1/, and so on, are replaced by
/etc/php5/ and so on.