A site document library is where you store and manage content, such as documents, images,
and videos.
You can upload content to share and work on with other site members. Users can view and work on this content, depending upon their permission settings.
Document library activities appear in the Site Content dashlet so you can see at a glance the content that's been added and updated.
You can also store content in the My Files and Shared Files areas and in the Repository, see Working with content outside the library for more.