We may well have asked ourselves this question—more than once!—and we've certainly heard others ask it, as we and they look outside for the answer instead of finding it within (or surrendering sufficiently for it to find us).
When we ask this question, what we're really wanting is an answer that is magnificent, dramatic, amazing, one that'll prove to the world we have worth and value. But it doesn't have to be any of those.
If we were to turn the question round to ask : "What is the purpose of my life?", the answer is very simple : To live every day to the fullest we can—for that day. To live each day consciously.…in the Now of each moment. When—at the end of that day—we can in all honesty say we have done our best to be the living expression of Love and Gratitude, then we can know we are living our life purpose.
And, along the way, we may indeed be doing something magnificent, dramatic, amazing, but that's merely a by-product of Being a life of Love and Gratitude.