Updated June 12th, 2019.
You want to type things like this…
… but you don’t know how to do it. Until now!
Since Mac OS 10.9 (Mavericks) there’s been an Emoji & Symbols menu item at the bottom of the Edit menu in many Mac programs. Choose that and you get this:
Choose a category on the left, and then choose a symbol/picture on the right. Double-click the picture to insert it into your document (Mail, Pages document, Messages). If double-clicking doesn’t work, just drag the smaller version (highlighted in the picture above) into place. You can’t drag the big version, for some reason.
BONUS: keyboard shortcut for showing the Emoji & Symbols palette is Control-Command-Spacebar.