How to type an em rule (em dash)

You could use a hyphen, but for clarity and to help your editor, use a proper em rule (em dash): —.

On a Mac, type an em rule by pressing option+shift+- (hyphen).

On Windows, type an em rule by holding down Alt while pressing, in sequence, on the number pad of your keyboard 0151.

In the Microsoft Office range software on Windows, you can type Ctrl+Alt+Num - (the minus key on the number pad).