Any file you save in W: as a .html file will appear on your very own website. You will need to use a text editor and save the file as filename.html.
The index.html is the default home page. Anything you save here can be seen by the public so you can send the link to the website to anyone and they can see it, including pictures and video.
Don't save anything in the W: that you don't want people to see.