Footnoting automatically formats footnotes if you follow these steps.  First, start typing a post as usual:

Then insert a footnote:

When you publish your post, the bracketed material becomes a footnote at the bottom of your post. If your viewer clicks the number in your text, the screen will jump down to the footnote. ¬†(He’ll need to scroll up a little if WordPress’s black bar appears across the top of the page.) It will look like this:

Have more than one footnote? does all the renumbering for you when you publish your post: