Hinduism believes after death of mortal body, the released spirit we called soul atman (which was immortal) manifests a new body to start new journey of life. With death of human body the spirit within does not die. The spirit, soul atman always was indestructible, could not be created or destroyed.
Immortality as per Hinduism scriptures belonged to spirit, soul atman existing in our heart. The physical manifest form was never designed by God to gain immortality. Furthermore the human form is just a medium for soul atman, the spirit within to cleanse itself of dross impurities within. There was no other purpose of human life.
It can rightly be said that purpose of human life is gaining enlightenment and finally moksha salvation so that soul atman, the spirit within could liberate self from cycle of birth and death forever. The journey of life truly belongs to the actual master and controller, the spirit within. It is dominated by ego human beings did not want to believe so.
Spiritual travelers after demolishing ego realized this actual fact of life that human body is just a medium for soul atman within to work out its karma.
The concept of afterlife does not exist in Hinduism. Hinduism believes that continuity of life was integral to spirit, soul atman existing in heart. Unless a soul atman reaches state of absolute purity it keeps rotating in endless cycles of birth and death. This cycle of birth and death comes to an end only when human beings gained enlightenment and finally moksha salvation.
Before starting its journey the soul atman was immortal and pure. In its cosmic sojourn it gained impurities and to regain its lost original pure prime pristine primordial form it starts manifesting life forms on life supporting planets like mother earth. Until life supporting planets like mother earth came into existence all souls atmans remained inert unable to do anything.
Of their own no soul atman could purify self and needs a medium to cleanse itself of dross impurities within.
Journey of spirituality is necessitated so that human beings can liberate their soul atman within forever. There was no other purpose of human life.