Metadata is the name of the attribute of a document. The concept of metadata is divided in two: metadata types (size, color, distance) and metadata values for those types. Metadata types are defined in the setup menu and associated with document types.
Then when a document is uploaded, a value for that metadata can be entered. There are two kinds of metadata type to document type relations: optional and required.
When a metadata type is optional for a document type, it can be left blank for a document being uploaded and the upload will still be successful. On the other hand required metadata type must be given a value or it will not be possible to upload the document at hand.
Examples of metadata type: Invoice number, color, employee id.
The data entry of metadata types can be set to allow any value to be provided (the default) or a list of possible values can be entered in the Lookup configuration option and users will be presented with a drop down list of options instead of the default text entry box.
If metadata types are setup to allow any value to be entered a validation option can be chosen to block the entry of invalid data. Metadata types also provide parsers which will not block the entry of data but are able to interpret and modify the value provided by the user to a conform to a specific format. An example of a provided parser is the date parser which will interpret and correct dates provided by users regardless of the format in which they are entered.