You make no mention of where you are looking in Xcode for the option.
First, you need to add the StoreKit configuration file to your project properly. Use Xcode -> File -> New -> File from template... Then on the template screen, scroll down to the "Other" section and select StoreKit Configuration File.
Once that file is setup, you make use of it by going to Xcode -> Product -> Scheme -> Edit Scheme. Then select the "Run/Debug" tab on the left. Then select the Options tab on the right. There you will see the StoreKit Configuration option where you can select the configuration file you created as described above.
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Developer Tools & Services
SubTopic:
Xcode
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