The Flashlight (looking like a glowing cube) is an equipment device that can be switched on and off to light up the area in front with white light.
Currently only players who have a "Pro"-status are given that Flashlight as a reward for paying. Early backers and players who have bought coins for money via the store before August 2nd 2016 have been automatically promoted to "Pro". The only way for new players to become "Pro" in Creativerse is by purchasing the "Pro"-DLC via Steam: http://store.steampowered.com/app/515710/Creativerse__Pro/
You cannot craft a Flashlight nor obtain it on any gameworld; the same goes for the Glider. If you have bought the "Pro"-DLC and can't find the glider (nor the Flashlight), then please exit the game and check your Steam game library. Make sure that there is a check mark next in the "installed" box next to the "Pro"-DLC; and if it isn't there, please click the box, so the DLC will work properly. Then start the game again and look at the equipment slots next to your inventory/bag.
The Flashlight has its own equipment slot to the right side of the character model and cannot be unequipped. When the player character is defeated, even in Hard Mode they will not lose the Flashlight (nor have it put into a Death Statue) when respawning at their Touchstone.
You can switch the Flashlight on and off with the "L" as the default key, which can be customized in your game options (TAB "controls").
If you look at your player character with 3rd-person view you will see the blue Flashlight (when activated) floating beside your character's head. Other players will also be able to see it. When you switch it off, it will not be visible though.
Despite it's blue color, the Flashlight emits a bright white light directed straight ahead and illuminates a few blocks in front of the player character.