The answer depends on what you are asking about. If you are asking about the entity, the actual being, the enlivenment, the life itself, then the best answer comes from a prayer we say a number of times a day. After eating certain foods, we say;

     "Blessed are You, L-rd our G‑d, King of the universe, Creator of numerous living beings and their needs, for all the things You have created with which to sustain the soul of every living being. Blessed is He who is the Life of the worlds."  

     This is the answer to what the actual life is; Hashem, He is the life within all!

     If you are asking, what is the value or purpose of life, then the best answer is that life is a golden opportunity, an opportunity to improve the world where we are, and an opportunity to gain a wonderful share in the World to Come, the world where we are going.   

     We are all on a journey, heading somewhere after we leave this world. Pack your bags carefully. We don't take our property with us. All we take are our deeds.