How does the Craft CMS built-in web server works? I just found this while using ./craft help in the Craft CMS command line utilities:

- serve                                      Runs the PHP built-in web server.
    serve/index (default)                    Runs PHP built-in web server.



How to use this built-in web server?
How can I edit these web server
settings?
Can i use multiple of these web server at once?


At this time of writing, I didn't find any documentation about that.

I'm using the latest version of Craft CMS (Craft Pro 3.3.17) under Mac OS (10.14.6).
This just launches PHP's built in web server, documentation for it can be found here: https://www.php.net/manual/en/features.commandline.webserver.php

You can use php -s localhost:8000 instead

You can see available settings by running php -s

Yes you can run multiple versions on different ports

Hope this helps!