What is in-app purchase (itunes connect)

I submitted my app via application loader and it is waiting for review. I noticed an option called: in app-purchase. What is this?? Will I have to fill this in, because I already filled in the add app form. So once the app is accepted will it be in the app store. Or will i have to fill this out? THank you, rep开发者_开发百科ly please and bye. ***BY THE WAY MY APP IS FREE SO DOES IT MATTER?

In App Purchases (IAP) are a way to have your users pay for additional functionality. If you have not implemented StoreKit for that then you don't need to bother with this button.