How do I enter superscript text with Preview's PDF annotation feature? I can add text to existing PDF files with Preview. But how do I enter superscript text like 123m2 ?

This normally works by selecting the appropriate menu entry



or shortcut, but I don't find such an entry with Preview and the shortcut does not work either.
I think you need to input Unicode superscripts via the Character Viewer or a text replacement shortcut.  Superscript 2 is U+00B2  ²