No more pain of unlocking your phone and then tapping on the flashlight app to turn it on when there is a sudden power cut or you are in the dark. Its very easy on your Moto G5 Plus.
You could turn the flashlight on/off with two chopping motions, Hold your phone tight and make two quick chopping motions (a quick firm handshake)
To feature is by default turned on, try the above steps to see if it works. Else here are quick steps to turn this feature on. Go to the Moto app in your app drawer, tap Actions and tap on Chop Twice for Flashlight, switch it on. Tap Show me how button at the bottom of the screen to try it out.
You could also turn off this feature, but unfortunately there is no separate app for Flashlight, unless you download a third party app from the Playstore. To use the Flashlight chopping is the only option.