The App Store is a place where mobile users can download and update most apps. From the App Store, you can download Mario Kart Tour and Super Mario Run.
The App Store is a also a great (and usually the default) way of making purchases and keeping track of them. Almost all mobile subscriptions, such as the Gold Pass, link directly back to the store.
Each mobile device has its own app store (most Android-based phones use the Google Play Store, with the exception of Samsung Phones which uses its own Galaxy Store with the option to also use the Google Play Store); however to avoid overcrowding in this article, we will only discuss popular first-party app stores (other less-popular stores will likely function similarly to one of these, with maybe a few missing features at most):
App Store[]

The App Store is an app on iPhones where apps can be downloaded. The App Store is not available on Android phones, and purchases are linked directly to your Apple ID, so you can access them from whatever device you are using. However, in Mario Kart Tour, purchases are also directly linked to your Nintendo Account, so you need to ensure that you are logged in here, too.
Before a court ruled that Apple must allow third-party downloads as the result of a legal battle between Apple and Epic Games, the App store was the only way an iPhone user could download apps.
Google Play Store[]

The Google Play Store is an app on Android Phones where apps can be downloaded. The Google Play Store is not available on iPhones, and purchases are linked directly to your Google Account, so you can access them from whatever device you are using. Similarly, in Mario Kart Tour, purchases are also directly linked to your Nintendo Account, so you need to ensure that you are logged in here, too.
Unlike iPhones, Android phones can download apps outside of the Play Store; Android also supports downloadable third-party app stores.