The Unreal Engine developer documentation contains most of what you'll need to use Unreal Engine to target Android devices.
The Android Quick Start guide covers most of what you'll need to begin Android development, including:
- Creating a mobile project
- Configuring the project to target Android
- Setting up the editor for mobile renderer previews
- Launching on an Android target device
- Packaging your Android build into an APK for testing
If you're using Windows as your development platform, Unreal integrates with the Android Game Development Extension for Visual Studio.
Packaging your project
Play Asset Delivery
The Google Play Asset Delivery reference covers how to enable Play Asset Delivery in your project, how to designate rules to create asset chunks that will become asset packs in the Android App Bundle, and how to take advantage of install-time, fast-follow, and on-demand assets.
Google Play Billing
Unreal 4.25 and higher integrates the Android Frame Pacing Library, which is part of the Android Game Development Kit. The Mobile Frame Pacing article explains how to enable the Android Frame Pacing Library, and how to control frame pacing from C++ code.
The Rendering Optimization for Mobile guide covers guidelines and best practices for optimizing mobile performance, including when to use normal maps vs high-vertex meshes. It covers the basics for reducing draw calls, mesh count and material id count, as well as material complexity, optimizing texture resolution, boot time, and package size.