Metadata is "data that provides information about other data". It is not the content of the data itself, but rather structured reference data that helps to sort and identify attributes of the information it describes. Metadata can be created manually to be more accurate, or automatically and contain more basic information. There are many distinct types of metadata, including:

• Descriptive metadata: This is the descriptive information about a resource. It is used for discovery and identification. It includes elements such as title, abstract, author, and keywords.

• Structural metadata: This is metadata about containers of data and indicates how compound objects are put together. For example, it describes how pages are ordered to form chapters. It describes the types, versions, relationships, and other characteristics of digital materials.

• Administrative metadata: This is the information to help manage a resource, like resource type, permissions, and when and how it was created.

• Reference metadata: This is the information about the contents and quality of statistical data.

• Statistical metadata: This is also called process data, and may describe processes that collect, process, or produce statistical data.

• Legal metadata: This provides information about the creator, copyright holder, and public licensing, if provided.

Metadata has various purposes. It can help users find relevant information and discover resources. It can also help organize electronic resources, provide digital identification, and archive and preserve resources. Metadata is used for various types of data, including computer files, images, relational databases, spreadsheets, videos, audio files, and web pages. The use of metadata on web pages can be very important, as it contains descriptions of the pages contents, as well as keywords linked to the content. This metadata is often displayed in search results by search engines, meaning its accuracy and details could influence whether or not a user decides to visit a site.