This document discusses different types of documentary films and their key features. It describes fully narrated documentaries that rely on a voiceover, fly on the wall documentaries that aim to show an unseen perspective, and mixed documentaries that use interviews and narration. It also mentions self-reflexive, docudrama, and docusoap documentaries. Key features that all documentaries contain according to the document are observation, interviews, mise-en-scene, dramatization, and exposition.