Difference between a List and a Library in SharePoint

The main difference between a Library and a List is that an item in a Library must

contain a file.

The document library mainly it used to store files and it is accompanied by metadata for the respective items in the document library.

The Custom Lists/List type is used mainly to store the data/information.

The Document Library always provides the version  of the files which the items are created in the document library.

In both the cases the content types can be associated.