Several OEMs are beginning to adopt some of our favorite customization features. This is great because it means that we no longer need to root our phone just to get some basic customization options. One of the standout customization features on the LG G4 is the ability to add custom app shortcuts to the G4's lockscreen. It comes out of the box with some of LG's apps. You can replace these with up to five of your own.
To change apps on lockscreen go to the settings tab, then go to display, go to home&lock, then go to Lockscreen. In the next menu go to settings, shortcuts. Then simply tap the icon you would like to change. You can also disable it entirely. You can also rearrange your icons. The only downside to this is the fact that if you are using any kind of PIN or lockscreen security you won't be able to use the custom lockscreen shortcuts.