The document discusses how to extend Oracle SaaS applications like Oracle HCM Cloud using Oracle Visual Builder Cloud Service (VBCS). It covers how to build an extension with VBCS, integrating it into HCM Cloud by adding a new page entry via the structure editor or embedding the VBCS application on an HCM Cloud page using the Application Composer tool. The document also provides a high-level overview of VBCS and how it can be used for both web and mobile application development without any code.