It depends on a person. For all it is fulfillment of one's duties. Otherwise it can vary, merging with the universal spirit, being in proximity of the universal spirit of one's chosen God or Goddess, and for me as an atheist Hindu, understanding life (which I have already done). I am a person of science. For me, this is the only life. After death, my body will disintegrate and the molecules will disperse in the environment. They would not come together again, so that is the end of the individuality of Aupmanyav. I do not believe in God, soul, birth and death, heaven and hell, judgement and punishment, end of days and resurrection/reincarnation. We are a story of continuous change since 13.78 billion years ago when inflation took place and will continue for many more billions of years. So, in a way, what constitutes us is already eternal.