Elastic Agent Standalone Configuration Input types logFile and filestream difference

Elastic agent reference config file:

Trying to setup standalone agent. came across few questions:

  1. In the inputs section, I have type as logFile and filestream, would like to know the difference and when to use which as both point to files.
  2. What are the types of inputs values (some documentation I can refer to )
  3. The streams section under each input, Is this a required setting ? If doesn't specified it collects all the data or no data at all?
  4. Also, does streams (Data stream fields under streams) are necessary ?