Use of the Documents Tab

A document library is a place to store files without attaching them to accounts, contacts, opportunities, or other records. Each document in the document library resides in a folder. The folders attributes determine the accessibility of the folder and the documents within it.
To learn the different ways files are used in Salesforce, see Differences between Files, Salesforce CRM Content, Salesforce Knowledge, Documents, and Attachments.

Clicking on the Documents tab displays the documents home page

Under Find a Document, enter keywords to search for a document.
In the Document Folders section, select a folder to view all the documents contained in that folder.
The Recent Documents section displays the last ten or twenty-five documents you viewed, with the most recently-viewed document listed first. This list is derived from your recent items and includes records owned by you and other users. Toggle the Show 25 items and Show 10 items links to change the number of items that display.
In the Recent Documents section, click New to upload a new document.