How to generate Item ID/Package ID/Monthly Subscription Package ID/Yearly Subscription Package ID for In-App Purchase?
Follow below mentioned steps to find Item ID/Package ID/Monthly Subscription Package ID/Yearly Subscription Package ID for In-App Purchase:
Begin by logging into your Development account, which can be found in your iTunes Connect page on Apple’s website.
Once in, find the My Apps application tab.
All of your created applications will appear here.
Select the features tab. Underneath the features tab are your in-app purchases. Click on the plus sign to add in-app purchases.
Next, you have the option of choosing the type of in-app purchase you would like to create.
Update the in-app purchases with the relevant information.
Once the purchase item is created, a Product ID can be found in the information section.