Since forever is a really long time there's really no way of preserving chocolate so it lasts forever.
But you can help keep chocolate fresher by wrapping it tightly in plastic wrap and keeping it in a sealed container.
Keep the chocolate away from light and store the chocolate in a cool and dry place but avoid putting the chocolate in the refrigerator because the refrigerator can decrease the shelf life of the chocolate.
However still chocolate will start losing it's freshness after a year of storage so it's best to eat the chocolate within a year for the best results.
I couldn't keep chocolate for more than 6 months myself before Indulge and eat that delicious chocolate.