On the top of the article you can see additional information: author, creation date, category and so on. All this information can be hidden.
Content > Articles Manager > click the article name > select No or hidden in the area Parameters (Advanced)
Under Article you can find navigation. You can hide it: Menu > Main meniu (or Right meniu or other menu link) > click the article name > in the row Show navigation select Hiden - it's Parameters (Component) area on the top right.