if I write a document in, say, Word, and copy it to an email, why does the line spacing, and indents have to go haywire?

Why can I not select the font, and size, of text in the new arrangement? I can only get a small number of options, 'tiny, small, Large, x-Large and Huge' and Modern, Modern Wide, Classic, Classic Wide, Courier New, Garamond and Lucida Console. A poor choice, which has already compromised by business address (see below) which looks awful now.