PHP (Hypertext Preprocessor) is a server-side scripting language primarily used 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 perfect for creating dynamic, interactive websites.

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

• Your browser requests a page from the server.
• The server processes the PHP code embedded in that page.
• The server executes database queries, calculations, or other logic.
• The server sends back pure HTML to your browser.

This process allows websites to display personalized content, handle form submissions, manage user logins, and much more.

For your hosting to support PHP, you need:

• A web server (like Apache or Nginx) with PHP installed.
• Proper file extensions (.php for PHP files).
• Often, a database like MySQL for storing data.

Most modern hosting plans include PHP support by default. Popular platforms like WordPress, Joomla, and Drupal are built using PHP, making it one of the most essential technologies for running modern websites.

Remember: Since PHP runs on the server, you won't see the actual PHP code when viewing a page's source in your browser – only the HTML it generated. This provides both security for your code and performance benefits for your visitors.