Quick answer
An APK is the file format Android uses to install apps. For Play Store releases, Google prefers the App Bundle (AAB) format.
What it is
An APK is a file that holds an Android app's code, images, and settings. For Play Store releases, use AAB. For direct installs, use APK.
Why it matters
For Play Store releases, use AAB. For direct installs and testing, use APK.
How to use it
- Build AAB for Play Store releases.
- Use APK for direct installs and testing.
- Sign the file with the right certificate.
Examples
- Play Store releases use AAB.
- Direct installs from a website use APK.