The 'php.ini' file is the default configuration file for running applications that require PHP. It is used to control variables such as upload sizes, file timeouts, and resource limits. Hosting providers and developers can edit the php.ini file to change configuration settings according to their specific needs. The settings in this file dictate how PHP scripts are executed on the server, affecting aspects like security, performance, and resource usage. Customizing the php.ini file is essential for optimizing PHP applications to suit different hosting environments.
