“ ”
The curves that open and close a quotation — the straight key flattened both.
The typewriter had a single key, so the straight quote came to both open and close. Typography always had two gems: “ (U+201C) opens, ” (U+201D) closes, each curved its own way.
Word processors swap them for you — that's smart quotes — but raw HTML, code and forms don't. The entities are “ and ”; the label carries the shortcuts.
Wrong: "Quote properly", asked the typographer.
Right: “Quote properly”, asked the typographer.