There are three different shortcodes to add a separator to your text:

[ hr ]

The hr adds a line to break the text in two part (it means in facts “horizontal rule”).

[ totop ]

The totop element is very similar to a hr but it displays a link to automatically scroll to the top of the page.

[ clear ]

The shortcode above simply adds a div:

<div style="clear: both;"></div>

to your page, very useful when you need to separate floating elements.