There will be some situation to change the maximum upload limit or memory limit for them, so it is good to create a php.ini for them and change the settings there so that the server wide php,ini will stay without any change. In this method , a custom php.ini in a suphp enabled cpanel server.

First check whether the suphp is enabled on your server .
Type the bellow command and see suphp is enabled or not.

/usr/local/cpanel/bin/rebuild_phpconf –current

If suphp is enabled then you need to copy the main php.ini to the home directory of the specified user.
You can find the location of the main php.ini using the below command.

php -i | grep php.ini

It will list the location of the php.ini.Also you can create a sample php page and load it on the
browser and search for the location of the php.ini file.
To create the sample php file create use any file with the extension .php in the user’s public html
and put the below in the file

Also you need to change the ownership to the user and then load it in the browser
site.com/info.php

Next copy the main php.ini file to the user home directory

cp -pv /usr/local/lib/php.ini /home/username/public_html/php.ini
(where /usr/local/lib/php.ini is the main php.ini)

chown -v username:username home/username/public_html/php.ini
Then open the .htaccess file from the user’s public html directory.If the file is not there just
create a new .htaccess and add the below to that

suPHP_ConfigPath /home/username/
replace the username with your specified username)
Then you are ready to use the custom php.ini. Edit this php.ini and you can see that the domain is using the settings from this php.ini.