Our primary purpose in life is to live, to be present, to be conscious and experience every moment.
Then, of course, there are secondary purposes, but those secondary purposes are all just forms, and all forms come and go, both physical and mental.
We are conditioned to strive endlessly to pursue those physical and mental forms at the cost of experience the real life that is this present moment. Everything else lives in our mind and is either a memory of the past or a projection into the fantasy that is the future.
The universe and consciousness are permanent, everything else will dissolve and go, including our thoughts.
Our purpose is to be.