Autobiographical is the describing word for writing, films, or songs that tell the maker’s own life. An autobiographical book is an autobiography: the writer is the “I” in the story. People also use it more loosely, when a novel or a film is not a strict true record but still clearly draws on the maker’s own childhood, family, or work. It can sound a little bookish; in everyday talk someone might just say “it’s about her own life”. It is not the same as biographical, which is about someone else’s life.