A document library is a place on a SharePoint site where users can create, collect, and update files with others. The libraries may be custom modified and allow different access levels.
A document library is a place on either a SharePoint Online or Sharepoint Server site where users can create, collect, and update files with others.
The libraries may undergo custom modifications:
- their layout may be modified either via Sharepoint settings options
workflows: https://www.google.bg/search?q=sharepoint+workflow&oq=sharepoint+workflow&aqs=chrome..69i57j69i65j69i59l3j0.5440j0j7&sourceid=chrome&espv=210&es_sm=93&ie=UTF-8
which can be created either directly on Sharepoint site or via Sharepoint Designer: http://office.microsoft.com/en-001/sharepoint-designer-help/create-a-workflow-HA010100591.aspxor custom solutions
Access to the library is granted on the basis of permissions which can be granted to internal Sharepoint users or external. The permissions have different levels, such as read-only and contribute: http://office.microsoft.com/en-001/windows-sharepoint-services-help/permission-levels-and-permissions-HA010100149.aspx
Access to the library may be granted for a document, list item or a whole folder: http://office.microsoft.com/en-001/sharepoint-server-help/manage-permissions-for-a-list-library-folder-document-or-list-item-HA010021564.aspx
You may also grant access to external users (given right permissions) http://office.microsoft.com/en-001/sharepoint-server-help/sharepoint-document-libraries-i-introduction-to-sharing-files-RZ010234528.aspx?section=3
Sharepoint libraries accept selected file types and some document types, like .aspx may be added to a Sharepoint library: http://office.microsoft.com/en-001/office365-sharepoint-online-small-business-help/types-of-files-that-cannot-be-added-to-a-list-or-library-HA101907868.aspx
Their content may be accessed by apps you are developing, e.g. using NAPA, Visual Studio: http://msdn.microsoft.com/en-us/library/office/fp179930.aspx
