Why Is My iPhone Showing A Small Facebook Icon Located At The Bottom Left Corner Of A Locked Screen. Here's The Answer.
Suggested Apps are, mostly, location based and it is part of iOS 10 feature. It determines your location via GPS (Global Positioning Satellite) and will suggest Apps that you will most likely use. So, for example, when you are at home it will suggest Facebook or when you are at Walmart, it will suggest Walmart App.
You can turn this entire feature off but not selectively. There is also a feature called Handoff which works with the Apple Watch. I’m not sure about how it works with a Mac yet, but in your case, it’s a suggested app.
You can us this to remove other Widgets you don’t want access to from the Lock Screen, but must have a passcode or fingerprint Touch ID to protect your device.