Go to Settings > Security and toggle on "Unknown Sources." This allows you to install apps from outside the Google Play Store.
Facebook Lite is a lightweight version of the Facebook app designed for low-end devices, slower networks, and older Android versions. For Android 4.1.2 (Jelly Bean), using a compatible, secure APK can provide a faster, lower-data experience while preserving core Facebook features: news feed, messaging (via Messenger Lite or integrated chat where supported), notifications, profile access, and basic media upload. Facebook Lite Apk Android 4.1.2 High Quality
: The app size is typically under 3 MB, taking up significantly less space than the standard version. Go to Settings > Security and toggle on "Unknown Sources