If you need free wifi tether and are still on a grandfathered unlimited data plan you will have to modify your hotspot app to get it working on the LG G4. The method for doing so is actually pretty simple though. You will need to be rooted and have a root file browser installed. Grab the apk from the link below, move the apk you just downloaded to system/app/hotspotprovision, and then set the proper permissions. This is super easy and does not require you to enter any commands.
via XDA