In order to write a great biography essay, you'll need to develop a thesis statement about them and write supporting paragraphs with information about their life and work. Finally, a conclusion will help show the lasting impact they've had.
The person you choose to write about should be someone famous. Since you'll need to do research about them, they need to be someone who you can find articles and books about. It would be best if the person is someone you're interested in. That way it will make it easier for you to get excited about doing the research.