With the Extensibility apps, you can create custom fields, data source extensions, and implementation descriptions for specific business contexts to enhance pre- delivered applications that are extensible to adapt them to your business needs.
You can also create custom CDS views based on pre- delivered data sources. The data of an application is distributed across several database tables. Using CDS views, you can merge the data from different data sources and rearrange the table fields according to application-specific needs.
You can create custom business objects with UIs. You can also add custom logic to custom business objects. You can thus create your own applications based on custom business objects.
You can use Custom Analytical Queries to create new queries or reuse predefined queries. You use fields from CDS views to create a query.
Extension items can be transported with the apps Export Software Collection and Import Software Collection to be productively available und usable.
Nate: You can extend applications and their UIs, reports, email templates, and form templates only if the applications that you want to extend are extensible.