How does web server differentiate between request for static and dynamic web pages?

The idea of static and dynamic web page requests came to me from an example to explain the anatomy of dynamic request mentioned in the article Client-Server Overview-Learn Web Development | MDN where the author says:

The Web Server detects that the request is "dynamic" and forwards it to the Web Application for processing (the web server determines how to handle different URLs based on pattern matching rules defined in its configuration).