Metadata is "data that provides information about other data". In other words, it is "data about data". Many distinct types of metadata exist, including descriptive metadata, structural metadata, administrative metadata, reference metadata, statistical metadata. and legal metadata.Descriptive metadata is descriptive information about a resource. It is used for discovery and identification. It includes elements such as title, abstract, author, and keywords. Structural metadata is metadata about containers of data and indicates how compound objects are put together, for example, how pages are ordered to form chapters. It describes the types, versions, relationships and other characteristics of digital materials. Administrative metadata is information to help manage a resource, like resource type, permissions, and when and how it was created. Reference metadata is information about the contents and quality of statistical data. Statistical metadata, also called process data, may describe processes that collect, process, or produce statistical data. Legal metadata provides information about the creator, copyright holder, and public licensing, if provided.