An Apple Arcade subscription is required to download Angry Birds Reloaded. Apple Arcade is a subscription service provided by Apple that grants access to hundreds of mobile games for a monthly fee. Once subscribed, you can play hundreds of games whenever you want. There are no IAPs or in-game advertisements.
You can check specific pricing in your area by opening the Apple App Store on your device and then tapping the ‘Arcade’ tab. More information regarding Apple Arcade can be found here: