The purpose of our bodies is to carry and propagate genes. But, in the sense of taking self-awareness and the capacity for abstract thought into account it's about whatever we decide it's about. For most of human history it's been about finding enough food to not die, and not getting eaten by anything, and not getting killed by anyone, and not falling off of anything, and not freezing to death, and finding a better cave, and having sex.
Now people make it about everything from dying for their god, to serving their community, to smoking weed and speed-running Resident Evil.
What a time to be alive.
Whether you believe in the bible or not life is about work, finding a partner, sometimes having children, spending time with friends and being part of a community.
I would encourage you to read the Gospel of Mark in the bible as it is the shortest gospel. Mark will give you a snapshot of what many believe life is about and how life should be lived.
Many christians and non-christians express issues that cannot be known as fact. We all have faith in something and should investigate differing points of view.
https://www.biblegateway.com/passage/?search=Mark%201&versio...
But if God isn't actually there, that's all futile. The biggest thing would then be the universe - physics, maybe? But humans are personal, and an impersonal universe is cold. So I would say, if not God, then human relationships.
That being said, I like to think of everything in life as a means, rather than an end. The people I surround myself with, the material possessions I bring into your life, the food and water I consume and the ideas I exposed myself to can either enhance my existence or become clutter and crutches. The old saying "the things you own end up owning you", applies to all of the above. It is your decision if these things are tools or toys.
So while you're out there figuring out what the meaning of your life is, take stock of the "things" you've introduce and ask if they are enhancing your journey. This has been my criterion for abandoning bad habits, cutting out toxic people and getting away from social media (your question compelled me despite my better judgement).
The flip side to that is whether you are enhancing the lives of those you are around. Are you a coworker that elevates your teams, are you a supportive friend, are you a kind neighbor? You're presence is a gift you give to others.
I think in short to me at least. Life and universe is playful and beautiful. And life purpose is what you make of it.
This strikes me as not a good question, akin to Kent Brockman/Smartline's "Religion: Which is the one true faith?" Life doesn't have "a" meaning, assuming by "all about" you mean something in that ballpark. Meaning is always meaning -for-someone.
Or maybe you mean, what is most important. That too seems a matter of some person's values.