Fonts

The email body is created with a default font. You can change it by choosing a new default in Misc|Fonts. You choose a default proportional font, and a default fixed font. For some emails, such as emails containing lists of numbers, you need to choose a fixed font so that the numbers line up properly.

If you wish to load an email with fixed fonts, uncheck Proportional. In this case, not only are the fonts monospaced, but also the carriage returns at the line ends are not stripped away. This is useful if the email contained a list of items, or program code. 

When email is sent, plain text is used, and so the fonts are ignored.