I expect the best way is to use HTML code to format the text. You have to do it long-hand, as there's no sort of WYSIWYG editor.
So for example: <br/> is a line break, <p> is paragraph. But doesn't pressing the enter key on your keyboard cause them to go to the next line?
<br /> and <p> is all you need really. Others for text formatting e.g. bold : <strong> or <b> for bold, underline: <u> for underline</u>, <i>italics</i> or more recent versions of HTML use <em> for italic text</em>