When you setup a new wordpress site, .user.ini file is auto generated with ideal php settings for PHP memory limit, upload max file size, max execution time, maximum input variables etc...
You can change PHP settings for your apps by editing a file named .user.ini in your app's web root directory.
/srv/users/APPNAME/apps/APPNAME/public/.user.ini
Using a .user.ini file is the best and safest way to customize PHP settings for an app. Unlike modifying global configuration files, using a .user.ini file can't break your server and does not require you to restart PHP.