How do they do this? Online stores

How are video game developers able to add integrated online stores in their games that also connect with their website online store? Like how is this done?

Ie games like Drakensang Online, Guardians of Ember, Royal Quest

Like how do they put integrated online stores into their games

Not really sure, but why does it matter? On the PS4 I know you usually or always get directed to the PlayStation Store, which makes sense of course. I'm sure developers could take you anywhere on the Internet if they wanted to. Just need the game connected to the internet, obviously.

@SoNin360:

I'm looking into developing my own MMORPG

Uh, simple programming? It's not magic.

@nethernova:

Like what? What ideas are there that are put into it to make it work?