How to create a Product ID on iTunes Connect?

The In-App Purchases form is used to generate In-App Purchase products. It contains a Product ID field that must be filled. Use this field to specify the product identifier for your product. Follow the steps below to create a product identifier:

Step 1. Log in iTunes Connect

Log in to iTunes Connect, then navigate to the Manage Your Applications module present in the home page. iTunes Connect takes you to the Manage Your Apps page, which contains a list of all your applications.

Step 2. Create New In-App-Purchase

Select the application for which you want to create In-App Purchase products, then click on the Manage In-App Purchases button in the ensuing page for this application, then click on the Create New button in the next page.

Step 3. Select a type for In-App-Purchase product

Select Non-Consumable type for your In-App Purchase product.

Step 4. Input Reference Name and Product ID

After clicking Select button, iTunes Connect takes you to the In-App Purchases form, which contains a Save button. Fill out the Reference Name and Product ID in that form.
Important: Please be sure to create a new Product ID for each issue. Do not use the same Product ID for two or more issues.

The reference name will be displayed in iTunes Connect and in sales and trends reports. It will not be displayed on the App Store. The reference name cannot be longer than 255 bytes.
Product ID is a string identifier that can only contain alphanumeric (A-Z,a-z,0-9), underscore (_), and period (.) characters. You can use any sequence of these characters for your identifier. However, we recommend that you use the reverse domain name style (for example, com.companyname.appname.productid) when creating your identifier.
Note: This Product ID should be input in Mag2GO. Please be sure to use the same string identifier on both of iTunes Connect and Google Play.
Important: You cannot edit a product identifier after you have created it. Furthermore, you cannot reuse product identifiers for products that have been rejected during App Review.

Step 5. Select Pricing and Availability

Please select Yes for Cleared for Sale item. Then enter the pricing and availability details for your publication.

Step 6. Add Language

Click Add Language button. iTunes Connect takes you to the following screen.

Input all 4 fields and click Save button.

Select No for Hosting Content item.

Step 7. Add Screenshot for Review

Before you submit your auto-renewable In-App Purchase subscription for review, you must upload a screenshot. This screenshot will be for review purposes only. It will not be displayed on the App Store. Screenshots must be at least 312x390 pixels and at least 72 DPI.

Click Choose button to select the screenshot you have already made on iPad/iPhone.

The screenshot must show the Price button. It should be as similar to the following one.

Click Save button and then Submit for Review button. Now the Product ID has been created.

The last thing you have to do is input this Product ID in Mag2GO. Please open Issue Properties dialog and input the Product ID like the following screenshot.