たぶんそれです。 https://developer.apple.com/library/archive/documentation/Miscellaneous/Reference/EntitlementKeyReference/ApplePayandPassKitEntitlements/ApplePayandPassKitEntitlements.html のIn-app provisioning of payment cards.+PKAddPaymentPassViewController使えばアプリ内でApple Payの登録画面を呼び出せるって認識で合ってるんですかね？

Apple Pay and PassKit Entitlements

Describes the entitlement keys for App Sandbox, iCloud, Push Notifications, and shared app containers.