Facebook Lite is a small, lightweight version of the main Facebook app that Facebook offers in some regions. Unfortunately, not everyone can get the app, so even if you wanted it, you can’t download it from the Play Store. And we can understand why you’d want to avoid the regular Facebook app.
Downloading from third-party sites is one option to get around this, but that’s always a risk. Malwarebytes found that the Facebook Lite APK being distributed by some sites contains malware that sends user data to Chinese servers and installs other apps without permission.
If you are downloading APKs from third-party sites, make sure they’re legitimate. But realistically, most people should avoid the practice entirely. And if you really want Facebook Lite, just open up Chrome and go to the mobile site.