Function

• A .PHP file provides a Web server with information about a website, script or other piece of code that is used to serve a website that performs a specific function.
  
  

Features

• PHP files, unlike other Web file formats, are executed entirely on the server, rather than on the user's computer through the browser. This gives PHP files extra security over other file formats, because their code cannot be directly copied by viewing a page's source code.
  
  

Identification

• A .PHP file extension may come in a few different formats, depending on the Web server and what an administrator has chosen to be interpreted as PHP files. However, a good identification rule of thumb is that anything with a "PHP" in the file extension name is likely a .PHP file.
  
  

Size

• A .PHP file can be of any size, from 0 kilobytes to a theoretical unlimited maximum size. However, the larger the file, the longer it takes to process on a server.
  
  

Benefits

• PHP files allow for custom scripting and complex websites to be created, and they interact natively with MySQL databases, making them perfect for generating dynamic websites that read and write information to and from databases.