Yes water is an essential part of your body and it helps with digestion , prevent constipation and keeps you hydrated.

I wonder what you mean by "help digestion." Your body needs water for nearly every function in some way or other. Our bodies are 70% water, and we are absolutely dependent on it for our survival. Every chemical reaction that happens in your gut, every cell of your body......it all needs water. So, although I don't understand what exactly you are asking, yes, digestion requires water.

Water helps everything, physiologically. In the case of digestion, staying hydrated allows you to produce the enzymes and fluid needed for digestion.

Water helps keep you hydrated