Many online IDEs offer the facility to click a button and it generates a new unique URL containing a live instance of the webpage, the moment the button was clicked. For example jsfiddle.

I wonder if anyone could help shed light on the easiest way to implement this facility.

EDIT

To clarify further, this online ide https://create.withcode.uk/, once you have written some code you can click the share button and choose to save to a new URL. This site will create a unique URL for that instance of the page including the code added by the user.

Sometimes this facility is known as a remix.