How long heavy cream holds its shape in the fridge long after it is whipped?

Add gelatin sheets to it to keep stiff peaks.

Kukla is so right, Nancy Silverton's Whipped Cream by Genius Recipes works like a charm.

One trick my mom taught me was to add a tablespoon or two of creme fraiche while whipping; it's thickness helps stabilize the final product and it keeps longer in the fridge.

Look up here on food52, Nancy Silverton's Whipped Cream by Genius Recipes, and you’ll learn how to keep whipped cream up to 4 days.

The heavier the cream and the longer it's whipped (stiffer), the longer it will keep. It's important to start with cold cream and keep it cold, both during whipping and after. There are other factors (homogenization, added stabilizers) as well so it's impossible to say how long your cream will last, could be hours, could be days. Good luck.

It will keep overnight in the refrigerator if you have to, but it's not ideal. I would store it in a stainless bowl, not in the chocolate cups unless it is just an hour or so during dinner. You might want to google 'how to stabilize whipped cream' to get longer lasting results. I've not tried before so no personal experience.