Most of the cameras has built in lens which is fixed and cannot be replaced. Some cameras comes with built in vary focal lens where you can zoom and adjust the focus but it cannot be replaced by a different lens.

The only camera that doesn't come with a lens and require purchasing lens separately is box camera. There are a lot of types of lens some are fixed and others have the zoom and focus adjustable (vary focal). Lens with auto iris option is better than others because it adjust the exposure time and rate depends on the light condition automatically.