This question is asked by truth seekers and many others from the beginning since ages together. It is answered or explained from various angles.
Famous Psychologist Maslow enumerates pyramidical hierarchy of needs, 1. basic physiological needs 2. safety needs 3. love and belongings need 4. self-esteem needs 5. self-actualization.
In Hindu shastra it is said, there is three ever deepening evolutionary purpose that culminates in living several human lives together. First, physical/ sensual gratification or objective pleasure; second, removing sorrow and suffering thus moving into joyful living; third, moksha or liberation from birth-death cycle while blissful living. Many believes other worldly or heavenly happiness after death as per karmic fruit also.
In another interpretation, it is explained as obtaining seven Sukhas that culminates to Mahasukh. Those are 1. su-sasthya 2. su-samparka 3. su-sampatti 4. su-santan 5. su-samman 6.su-sanskari nara-nari 7. swadeshe basabaskari; and finally, mahasukh that is ‘samadhi’ experience. These can be further explained in objective and subjective/ holistic mode. 1. Su-sasthya is not only absence of physical disease but integrated wellbeing of physical-mental-emotional-social aspects of life. 2. Su-samparka that not only extol self-esteem but also includes amiable relationship in shanta-dasya-sakhya-batsalya-madhur, different types of bhabas 3. Su sampatti is not accumulation of just meterial property or prosperity but includes sat-sampatti I.e., sam-dam-tittiksa-uparati-sraddha-samadhan 4. Su-santan is not just good looking and lamp some earning ward rather disciplined and values inculcating human being 5. su-samman includes Self-respect or atma samman along with social respect etc. Etc.
From another angle, purpose can be explained as roti-kapra-makan, sukh-sammriddhi-samman, shanti-swatantrata-samadhan, prem-ananda-nirban I.e., physical, mental-intellectual, emotional-soul and spiritual aspects of evolutionary objective to subjective fulfilment of human living.
Finally, the purpose of human life can be said as purposeless purpose, or just living in the now and here mode while accepting or surrendering or witnessing and becoming aware of whatever is happening in life at perpetual present like blood circulating, breathing from birth to death. In this concept, all human beings and nature are participating in a cosmic drama, dream, play or game that is going on without any motive and we must return to the source of nameless, formless, changeless spiritual entity ultimately completing unevolutionary/ evolutionary cycle, or must discover the director essentially realizing self or experiencing essential spiritual/ cosmic unity within and without.