For decades now, typographic sorts that were unavailable on typewriters have been available to everyone on digital devices. We’ve always had hyphens, but now we can also use dashes.
- Hyphen: joins elements of compound nouns and modifiers:
ne’er-do-well, cure-all, built-in, two-thirds. Hyphens at the end of a line of text also indicate that a divided word continues at the beginning of the next line. - En Dash: The width of an upper case N, the en dash is used by typographers to indicate a duration: March–May, 3:00–7:00
- Em Dash: The width of an upper case M, the em dash was represented on typewritten manuscripts with two hyphens, but now we can all type the em dash.
“The em dash is sometimes considered a less formal equivalent of the colon and parenthesis, but in truth it’s used in all kinds of writing, including the most formal—the choice of which mark to use is really a matter of personal preference.”
—Merriam-Webster