Where are file-information like "created" or "last edited" actually stored?
Information like "creation time" is called metadata.  The filesystem stores both the contents of the file and its associated metadata on the hard drive.  It has to -- if you reboot the computer, we need that information to persist, so it has to be stored somewhere that will survive reboots.  That place is the hard drive.

See https://en.wikipedia.org/wiki/File_system, How do Hard Drives Send and Recieve Data?, Reconstructing files from binary, Typical file structure, and a good operating system textbook to learn more about how filesystems work.