The LG G3 is receiving its Marshmallow update now, but unfortunately only in Poland. The information, which comes from LG's official Polish Twitter account, states that the update is now available to be downloaded. Included in this update is the new permission controls, Doze and many other improvements and enhancements.
If you have yet to receive the update, it may take a few days to hit your phone. If you want to check manually for it, you can do so by heading into your Settings, then About device and checking for the update there. Once you update, let us know in the comments below how it works out for you.
Source: LG Poland (Twitter)