Digestion of carbohydrates fats and proteins is completed and absorption of nutrients occurs in the

After the digestion of carbohydrates, fats, and proteins in duodenum, the digested nutrients are absorbed in the ileum.

Ileum is a section of the small intestine, after duodenum.

Food is absorbed by diffusion and active transport. Villi on the walls of the ileum helps this process, since it can increase its surface area and provide a good blood supply, thus increase the rate of absorption.

Note that water can also be absorbed in the large intestine, those water absorbed there are the ones that cannot be absorbed in the ileum.
However, not all water is absorbed as we can notice that faeces are wet.