config files in .Net

Web.config:--Basically this file is use for web setting or we can say web.config file contains setting to a web application.

Machine.config:--Settings to a computer and that help to configure all application into same machine.

Example:--
In a machine it can be more then one web application so each application will have one or more web.config files depend on configuration level of folders but in that system there will be one machine.config file.