3.1.1 In-App Purchase:
If you want to unlock features or functionality within your app, (by way of example: subscriptions, in-game currencies, game levels,
access to premium content, or unlocking a full version), you must use in-app purchase.
Apps may not use their own mechanisms to unlock content or functionality, such as license keys, augmented reality markers, QR codes, etc. Apps and their metadata may not include buttons, external links, or other calls to action that direct customers to purchasing mechanisms other than in-app purchase.
Apps may use in-app purchase currencies to enable customers to “tip” digital content providers in the app.
Any credits or in-game currencies purchased via in-app purchase may not expire, and you should make sure you have a restore mechanism for any restorable in-app purchases.
Remember to assign the correct purchasability type or your app will be rejected.
Apps may enable gifting of items that are eligible for in-app purchase to others. Such gifts may only be refunded to the original purchaser and may not be exchanged.
Apps distributed via the Mac App Store may host plug-ins or extensions that are enabled with mechanisms other than the App Store.
Apps offering “loot boxes” or other mechanisms that provide randomized virtual items for purchase must disclose the odds of receiving each type of item to customers prior to purchase.
Non-subscription apps may offer a free time-based trial period before presenting a full unlock option by setting up a Non-Consumable IAP item at Price Tier 0 that follows the naming convention: “XX-day Trial.” Prior to the start of the trial, your app must clearly identify its duration, the content or services that will no longer be accessible when the trial ends, and any downstream charges the user would need to pay for full functionality. Learn more about managing content
access and the duration of the trial period using Receipts and Device Check.