PHP (Hypertext Preprocessor) is a server-side scripting language designed specifically for web development. Unlike HTML or CSS which run in your browser, PHP code executes on the web server before the page is sent to the user's device. This makes it incredibly powerful for creating dynamic, interactive websites.

When you visit a PHP-powered page, here's what happens:

• Your browser requests a page from the server.
• The server finds the PHP file and processes the code.
• The PHP engine executes commands, which can include:
  • Pulling data from a database
  • Performing calculations
  • Generating HTML content
• The server sends the final, plain HTML to your browser.

Common uses of PHP include:

• Content Management Systems like WordPress, Drupal, and Joomla
• E-commerce platforms and shopping carts
• User login systems and form processing
• Creating forums and social networks

For hosting, PHP requires a server with the PHP software installed. Most modern web hosting plans include PHP support by default. The language is open-source, free to use, and runs on all major operating systems, making it a fundamental technology behind millions of active websites today.