Document Management is the quest to create order from the chaos of unstructured business data, this is what document management is all about.

Document Management Life Cycle
SharePoint is able to store and share document securely with various permission.
It has version control meaning that is can retrieve an older version of the file on an accidental save or if you just want the original.
Only the right people have access to documents and can interact with the document i.e. some won’t see it, some will see it but can only read it, some can see it and edit it, some can only print it (you choose the level of security)
Documents can be “tagged” to ensure that finding them is easier (This is via “Metadata” and creating various content types).