A: “Create” is a vague term. It could mean “design” or it could mean “manufacture.” Manufacture of packaging is done by whoever you get to print the game itself, so, like for the other elements involved, they will give you a template of the packaging layout (like a box laid out flat, or a plastic film packet laid out flat).

Design of the package would be handled by you, whether it means you doing the design work, or you outsourcing the art/design. In many cases, you might have different people doing the art vs. the design, and either one of them might be you.