Documentaries can use several features and take different forms. Key features include observation without interference, interviews to contrast with observations, and dramatization to portray inaccessible events. Common types are fully narrated documentaries using voiceovers, fly on the wall relying only on observation, and mixed styles using multiple features like interviews and narration. Docu-dramas combine reenactments with exposition but are limited by their fictional elements. Current affairs programs differ in their focus on daily news coverage within time constraints versus documentaries' in-depth investigations over longer periods.