Article: Minecraft Pocket Edition (PE) is available for iOS, Android, and Windows Phone. Select it from the search results. You will need to purchase Minecraft PE before you can download it. If you've already purchased it before, you can begin downloading it immediately. You will be able to find it on your Home screen or in your app drawer.

What is a summary?
Open the app store on your device. Search for "Minecraft Pocket Edition". Purchase it if you haven't already. Tap "Install" to begin downloading and installing Minecraft PE.