A transport request collects development objects and categories for export to your local computer or to an SAP transport system.
When you create a development object (ABAP repository object) in a non-temporary ABAP package, you must always assign the object to a transport request.
If you create an ABAP program using the creation wizard, the following dialog appears asking you to assign the program to an existing transport request or create a new transport request:
Changes to development objects from non-temporary packages are organized in tasks and take place in transport requests. A transport request records all changes to development objects. The assignment of a package to a transport layer ensures that the package is connected to the Change and Transport System, thereby defining the integration and consolidation system for its development objects.
With regard to the transport behavior of development objects, we have to distinguish between these three cases:
Transportable packages are assigned to both a software component and a transport layer. So-called "HOME objects" represent a special case. They can be transported within a system landscape, but are not designated for external delivery (customer delivery). Packages of this type are assigned to a transport layer and the specific software component HOME. All changes to transportable development objects are recorded in transport requests.