How to safely shut down or force shut down LG devices

LG Optimus GJ LG Optimus GJ
LG Optimus Zone LG Optimus Zone
LG Optimus L4 II LG Optimus L4 II
LG Optimus L4 II Dual LG Optimus L4 II Dual
LG Enact LG Enact
LG Optimus Vu 3 LG Optimus Vu 3
LG G Pad 8.3 V500 LG G Pad 8.3 V500
LG G Pad 8.3 LTE V507L LG G Pad 8.3 LTE V507L
LG Optimus L2 II LG Optimus L2 II
LG Google Nexus 5 LG Google Nexus 5
LG GX LG GX
LG Optimus L1 II Tri LG Optimus L1 II Tri
LG L40 Dual LG L40 Dual
LG L40 LG L40
LG L70 Dual LG L70 Dual
LG L70 LG L70
LG L90 Dual LG L90 Dual
LG L90 LG L90
LG F70 LG F70
LG G Pad 8.3 LTE VK810 LG G Pad 8.3 LTE VK810