The composition of hepatic bile is (97–98)% water, 0.7% bile salts, 0.2% bilirubin, 0.51% fats (cholesterol, fatty acids, and lecithin), and 200 milliequivalent/L inorganic salts.
It is stored in its reservoir - the gall bladder.
It's mainly used for as an emulsifying agent to aid in the digestion and absorption of fat.
Final answer: In humans, bile juice is secreted by the liver.