blank line between parapraphs

How can I insert blank lines between paragraphs in ver 2.7.1 using the buttons on the dashboard? On the the “Add A New Post” page, my WP command bar has buttons for Bold, Italics, Link, Underline, Image, Insert, etc. but there aren’t any buttons for <P> or </P>. I would use these commands much more frequently than italics or underline.

Is there a way to customize the buttons on the menu bar to include <P> or </P>.

Thanks.