Atman in Hinduism is the underlying Prana energy that manifests human form to cleanse self of dross impurities within. By itself an atman cannot purify self of its own and needs a medium, a body to work out its karma. Every atman (soul) manifested human body to reach state of absolute purity, regain its lost original pure prime pristine primordial form.
The human body, the human form is only a medium for atman within to reach cosmic end of life, the stage when after gaining absolute purity it reaches state of moksha salvation, liberating self from cycle of birth and death forever. A pure atman need not manifest a human body again. In absence of dross impurities within need to manifest a new body ceases to exist.
After reaching state of absolute purity if the enlightened soul left mortal frame, then liberated atman finally gains entry into kingdom of God (Vaikuntha in Hinduism).
Reaching state of absolute purity as an atman means becoming an enlightened one like Mahavira, Gautama Buddha or Jesus Christ and Prophet Mohammed forever.
Every atman in its cosmic life cycle manifests a maximum of 8.4 million bodies of which last 1.1 million manifestations occurred in human form. The cosmic journey for an atman truly is long indeed. In human form we can reach state of enlightenment in present life or postpone it for future manifestations of body by atman within.
The choice is ours. Human beings are imbibed with free will exercising which we can take final decisions in life, whether we want to continue in endless cycles of birth and death or want to liberate forever from cycle of birth and death.
When around nine years of age I finally decided to end this endless cosmic rotation in the cycle of birth and death and thus started my spiritual journey of life.