Online Documentation for Data Pump for PostgreSQL
Selecting data source type
On the first step of the wizard you need to select a data source type.
User Data Source
Selecting User Data Source creates a data source which is specific to this machine, and visible only to you.
System Data Source
Selecting a System Data Source creates a data source which is visible to any user, or service, logged into the machine.
Click the Next button to proceed to the Selecting driver step of the wizard.