dashes

Use an em dash (—) without a space on either side when a dash is used in the body of the text to signal a change or set off a series within a phrase. The seminar—attended by parishioners and clergy from throughout the diocese—focused on issues of racial justice. (Chicago style)

Em dashes are used in citations; in an epigraph, they follow the quote, usually on a separate line:
All shall be well.
—St. Julian of Norwich
See also epigraph