How to type a long/em dash `—`
This might be one of those that changes by language, but on a UK English keyboard [&amp; from comments, also US English], there are 4 dashes available from the key to the right of 0, Minus.

-  -  key alone (hyphen)
–  -    Opt ⌥  (en dash)
—  -    Opt ⌥   Shift ⇧  (em dash)
_  -    Shift ⇧  (underscore) 

Late Edit...
To complete the set, &amp; from comments...

 Ctrl ⌃   Opt ⌥   -  will give 'information separator one' which looks like a space "" &amp; doesn't even seem to print in here. You could, however use the keyboard replacement tool to turn that into a true minus sign...  −