SharePoint lists and libraries can store a variety of content on the site. SharePoint also has a user interface to customize what information you can collect from users to be attached as an item metadata.
In the scenario where the entire intranet or the department site within your organization requires a standard set of metadata to be collected with list and library items, content types are the easiest approach to implement the requirement.
With content types, you can define the type of business content your users will be interacting with. Once defined, you can also add a metadata field and any applicable validation to them just like we did for individual lists in Chapter 3, Performing Advanced List and Content Operations in SharePoint using PowerShell. Once defined, you can attach the newly created content type to the library or list of your choice so that newly uploaded or modified content can conform to the rules you defined on the site.