Why does it take time at all to download any Internet fIle?

It certainly does actually exist. Every item in a file exists as a number. There are 256 numbers and each is represented by a pattern of 8 bits. A bit is sent through the internet as a color of light and it has to be long enough for some electronic sensor to figure out what color it is seeing. If you have a telephone modem the file is sent as a whistle and some circuit has to analyze the whistle. When it gets to your computer it is converted to a pattern of magnetized spots on the hard drive.

All equipment is rated for the bits per second it can handle. Most of the internet is very fast, but your cable connection might be only a few million bits per second. A file of 100 MB would be 800 million bits so it takes 800 seconds to download it.