Usually you define your routes and then just assign different slug and id to them to make different “pages”. Example, you have a hotel booking site and the hotel details page looks like:
https://mysite.com/hotel.php?id=123&name=great+hotel
then you make routing to it which looks like:
/hotel/:id/:name/
and then your users can create different “pages” using routing and you can allow them entering different names slugified like:
https://mysite.com/hotel/1/great-hotel
https://mysite.com/hotel/2/hotel-name-here
https://mysite.com/hotel/99/some-name
so the “dynamic” part here is the slug and the id. The routing path is all the same.