Once you have set up your project for Unity Services, you can enable the Unity IAP service.
In the Services window, select In-App Purchasing.
Click the Enable button to enable In-App Purchasing.
The following error messages may indicate that Unity IAP is disabled in the Unity Cloud Services window, or that Unity is disconnected from the Internet:
To resolve these errors, first try reloading the Services window. A quick way to do this is to close it and then reopen it. Once reloaded, make sure that Unity IAP is enabled.
If this doesn’t work, try disconnecting and reconnecting to the Internet, then sign back into Unity Services and re-enable Unity IAP. Only users with Unity Services “owner” or “manager” roles for the registered organisation can enable the Unity IAP Service.
To import the Unity IAP package into your project, click Import.
When you import the package, a new folder called Plugins is automatically added to your project. This folder contains UnityPurchasing assets required to use Unity IAP.
Click Back to services to review the Services panel.
Make sure that that Analytics and In-App Purchasing are both labelled ON as shown below.
You can now begin implementing Unity In-App Purchases into your project.