Specific reference structures are defined for address parameters in BAPIs. You should copy these structures to use in your BAPI, especially if the underlying object type uses the central address management (CAM).
For more information see Address Parameters.

In BAPIs that cause database changes (for example, Change() and Create() BAPIs) you must be able to distinguish between parameter fields that contain modified values and parameter fields that have not been modified. This distinction is made through the use of standardized parameters.
For more information see Change Parameters.

The parameters ExtensionIn and ExtensionOut provides customers with a mechanism that enables BAPIs to be enhanced without modifications.
For further information see Extension Parameters and Customer Enhancements to BAPIs

Each BAPI must have an export return parameter for returning messages to the calling application. To provide application programmers with a consistent error handling process for BAPI calls, all return parameters must be implemented in the same, standardized way.
For further information see Return Parameters.

Standardized selection parameters are used in BAPIs that can be used to search for specific instances of a business object type (e.g. in GetList() ). These parameters enable the BAPI caller to specify the relevant selection criteria.
For more information see Selection Parameters.

The parameter TestRun is used in write BAPIs (Create() and Change() ), to check the entries for the object instance in the database before actually creating the object instance. The creation of the object instance is only simulated and data is not updated.
For further information see Test Run Parameters.

To transfer BAPI documentation texts (e.g. the documentation of a business object type), you have to create standardized text transfer parameters.
For more information see Text Transfer Parameters.