The Atma is the innermost essence, the true existence and identity of a being. Hindus call this subtle, conscious, invisible life-force Atman. Living being possesses consciousness due to the presence of the Atma(soul) in their bodies. The Atma is not to be confused with body or mind. In fact, the soul manifests itself as the energy or the life-giving force of the body. The human Atma (soul) is called Jivatma or self. Life starts when Atma enter the body. The human body perishes but the Atma is immortal. Bhagwan (God) is also called the Super Soul, the source and origin of the Atma(Soul). If the Atma is the energy that runs the body, Shri Bhagwan (GOD) is the sum of that energy. If Bhagwan is the fire, an individual soul is its tiny spark. Since the soul is a fraction of Bhagwan (God), all living bring are His manifestations. This is why Hindus see divinity in every living thing.
To simply explain it, Atma is the force Of life in the body. So when someone dies then only thing that is left is the body. The force that was in there that made the person feel and experience life is gone. So that is Atma. It is translated to the word soul but it’s not correct. Soul is only for humans but Atma is in humans and plants and germs and anything that is sentient being. Plus it has no weight, it cannot be touched by anything, it can’t get wet or have any physical shape or form. This is the Vedic way to explain Atma. The goal of every human being is to understand this Atma that is in the body and to experience it. So your true identity is the Atma and not the body. You are not the body but the Atma. When one attains this knowledge he must conquor all his senses to the material objects. Once a person become self realized then he can attain full enlightenment to fully understand Sri Bhagwan and once he leaves the body he attains God in full form and merges with him. This is the main goal of life which is to attain moksh or nirvana.