PHP is a server-side scripting language that is used to create dynamic web pages. It is executed on the server, and the resulting HTML is sent to the client.

Here is how PHP works:

1. The client (usually a web browser) sends a request to the server for a web page that contains PHP code.
2. The server receives the request and processes the PHP code. It runs the PHP code and generates the HTML output.
3. The server sends the HTML output back to the client.
4. The client’s web browser receives the HTML and renders it for the user to view.

In this process, the PHP code is never sent to the client. It is only executed on the server, and the resulting HTML is sent to the client for rendering. This allows PHP to be used for tasks such as accessing databases, performing calculations, and creating dynamic web pages.