Development Objects and Packages 
When you work with the Workbench, you work with development objects and packages.
Development objects are the individual parts of an ABAP application. Some examples of development objects are programs like reports, transactions, and function modules. Program components such as events, screens, menus, and function modules are also development objects. Finally, objects that programs can share are development objects as well. These shareable objects include database fields, field definitions, and program messages.
A package is a container for objects that logically belong together; for example, all of the objects in an application. A package is also a type of development object. An example of a package might be General Ledger Accounting.
When you create a new object or change an existing object, the system asks you to assign the object to a package.
Storing Development Objects
The SAP system stores development objects in the Repository, which is a part of the database.
When you complete work on a development object like a program, screen, or menu, you generate a runtime version of the object. This runtime version is stored, along with the object, in the Repository. An application consists of several runtime objects that are processed by the work processes in the SAP System.
In a standard SAP installation, development and live operation take place in separate systems. New applications are created in the development system and transported to the production system. Daily work takes place in the production system which uses run-time versions created in the development system.
The division between production and development systems is recommended because changes to an existing ABAP application take immediate effect. To prevent disturbances in daily work flow in the production system, all developments are carried out in development systems designed especially for this purpose.
The Transport Organizer
You use the Transport Organizer to move applications from the development system to the production system. The Workbench Organizer also provides version control and tracking. When you work with the Workbench, you will encounter safeguards provided by the Transport Organizer. A brief overview of these checks and how they affect the development process is provided in Development in a Team Environment .
See also
Package
Concept