How you will be remembered by others after you're gone is what is known as your legacy.
Our goal should be to strive to create a legacy for ourselves that will inspire people for generations to come. A useful tool for this is to brainstorm with the end result in mind. Imagine that you are dead and attending your own funeral ceremony. What will people say about you? How will you be remembered?
Putting yourself in this mindset will better aid you in designing your life purpose statement.