When editing an email message (and most content in Luminate Online) there are two types of editors you can use - the plain-text editor and the WYSIWYG editor. The WYSIWYG editor shows you a rendering of what your email will look like as you create it, and you can do basic text editing like change the font size and formatting. However, the plain-text editor is a simple text editor meant solely for HTML content. While it is just a text editor like notepad, unlike notepad it is setup to interpret HTML text only. So if you use this editor your HTML will be rendered as-is and any formatting you would like to use will have to be in the form of css code. HTML collapses white space, so if you are trying to edit your text via the plain-text editor any spacing and formatting that you insert is not going to translate to the final page -- when the HTML is interpreted by web browsers all the white space will be collapsed. If you are not well-versed in HTML/CSS or use an external HTML editor, you will want to use the WYSIWYG editor to handle any formatting for your email.