Document library
The Document library web part displays CMS.File documents stored under a specified path in the content tree. It enables live site users to use your website as a file repository where they can upload files from their local computers and let others access them. A typical use of this web part is on intranet websites.
The web part belongs to the Document libraries module. Full documentation of the module can be found in Kentico CMS Developer's Guide -> Modules -> Document libraries.