Use an em dash to set off an abrupt break in a sentence
Use an em dash to add emphasis
Use an em dash to insert a parenthetical aside
Use an em dash to replace commas, parentheses, or colons for stronger separation
Use an em dash to show an interrupted thought or cut-off speech
Use an em dash to introduce or expand on a list, explanation, or example
Use an em dash to indicate a range only when style guidelines allow it
Do not put spaces around the em dash in standard American English
Use consistent spacing and punctuation according to the style guide you follow