Mapping is one of the key features in any of the integration where two or more applications are talking to each other.
In most of the cases, the messages we want to transfer between two applications in integration have different data structures.
A visual mapper allows us to map field applications by dragging source fields onto the target fields. When we open the mapper for a request or response message in integration, the data structures are automatically populated with the information pulled from the source and target connections. We can expand and the load data structure levels on demand to display additional levels. There is no limit on the levels of display.
Oracle Integration Cloud Mapper

These maps are called transformation maps and use the eXtensible Stylesheet Language(XSL) to describe data mappings which allows us to perform complex data manipulation. A standard set of XPath functions are provided for you to define how data is modified when moving from one application to another.

The mapper supports both qualified and unqualified schemas (that is, schemas without elementFormDefault=”qualified”). Elements and attributes with and without namespace prefixes are also supported.

Elements and attributes for which mapping is required are identified by a blue asterisk (*) to the right of their names. To display only required fields, click the Filter , select Required either from Source or Target, and click Apply.