Youll need 1 shulker box and 1 anvil, along with some experience earned (at least 1). This achievement is buggy, and your best shot at unlocking it is renaming a coloured shulker box without using the quick move (Y). To dye a shulker box, simply get some dye and dye it at a crafting table (cannot dye it if its already renamed.)
Place the anvil on the floor, press LT to open it. Place a coloures shulker box in the spot on the left, then change the name. Pick up the shulker box on the right and move it to one of the 10 spots at the bottom of your inventory (whats on hand) and press A. This might take a few tries and it is nit guarenteed to unlock.