Literally, Metadata is data about data or more precisely it is information about the data that is not, business data. The classic example would be a database schema, which uses a precise language to describe the data held in the database.
In the software development world, the Metadata is used to customize or control the behavior of software systems. Software Products provide a varied levels of configurability into their systems to accommodate a broad range of needs.
Application Developer proffessionals can leverage the same approach to make applications more adaptable to changing business conditions. They incorporate metadata into their design thinking to create more agile business systems, whose behavior can be changed outside the software development cycle.
Check out more details on Metadata here.
Metadata: What It Is And Why It's Important