"The Purpose Driven Life" is a popular book that purports to answer this question.
Here's a more accurate and useful answer...
Any one of us is here because our biological parents had sex, our mother was fertile, one of our father's sperm beat out a few million other sperm to fertilize an egg, and our mother did not abort us.
It's up to each of us to find our own meaning and purpose.
The choice is ours. Not God's, not The Church's, not anyone else's.
Some choose to serve humanity by adding their voice to that of others working for change.
Some choose to try to destroy humanity.
Much of the time it's hard to tell which is which.
By far the most popular choice though, is to do nothing.
We immerse ourselves in work, sports, exercise, gardening and a host other pastimes in an effort to ignore societal problems that are depressingly troubling, largely because we feel helpless to solve them. We become terminally passive.
We're not going to find answers in a book or in a church or even on Google.
The answers are within ourselves.