Which nonfiction genre is defined as a story of real peoples lives, told by other people

Answer 1

The nonfiction genre you are referring to is known as "biography." A biography is a detailed description or account of someone's life, written by someone other than the subject themselves. If it focuses on the life of a specific individual, it's called a biography, whereas if it surveys the lives of multiple people or presents various life stories, it may be referred to as an anthology or a collective biography.