Request and manage promo codes - Offer promo codes - App Store Connect - Help - Apple Developer

Promo codes provide potential App Store customers or reviewers with a free copy of apps or in-app purchases (including subscriptions) on iOS, macOS, or tvOS. Promo codes can be redeemed on any App Store storefront where your app is available and are valid for four weeks from the day they’re generated. Each promo code can be used once.

Apple to let app developers offer free or discounted subscriptions via offer codes - The Verge

Implementing promotional offers in your app

Promo icon hi-res stock photography and images - Alamy, promo

Apple releases custom codes and unlocks influencers' referral capacity