Other people can tell us what they think the meaning of life it, but that is just their opinion. If enough people agree and they write about it and put it in a holy book, then it becomes The Truth. This makes it very easy for people who do not want to think for themselves or simply cannot do their own thinking. They can just follow some doctrine that they have been brought up with and that is good enough for them.
But without meaning that we bring to life, we are just like ants or bees, going about creating and destroying in our little hives, mindlessly going about one mechanical task after another. In the end, our lifeless bodies are tossed aside to make room for the next generation of insects. And what was the point, besides the furtherance of all the lifeforms on the planet?
Some might say that life has no meaning at all. “It just is” and we try to make sense out of it by assigning meaning. We intuit that there is too much pain and suffering in life for it to be completely meaningless. And so that is part of our quest as humans. To find our own reason for why we are on this planet. No one can do this for us. We must do it for ourselves and that is what makes life a growing and learning experience of constant change for the ones who dare.