Unlike a standard app, a full operating system like Android 6.0 cannot be installed as a simple APK file. You typically need the or an OTA (Over-The-Air) update file specific to your device model. Check & update your Android version - Google Help
Android 6.0 Marshmallow, first released in , remains a significant milestone in mobile history for introducing features like granular app permissions and "Doze" mode for battery efficiency. While newer versions have since surpassed it, many users still seek to download the Android 6.0 APK or firmware to revive older hardware or test legacy applications. How to "Download" and Install Android 6.0 android 6.0 download apk