Optional applications can help enhance Initially an ownCloud functionality. Some instance provides a minimal set of applications are available after the installation of ownCloud as “internal” in a “disabled” state(Files, Pictures). While other Many applications are “3rd Party” and are available as “one click” installations (from the ownCloud Application Store) that are automatically downloaded, installed, and “enabled” when via the ownCloud administration user account. Other applications have to be downloaded from the '''[https://apps.owncloud.com/ ownCloud administration settingsAppStore]''', installed, and "enabled" manually.

Applications internal to ownCloud "Core" applications are supported by the ownCloud project community developers where 3rd third party applications are supported “as-is” by their contributing authors. Many 3rd third party applications were developed for specific ownCloud release versions. In some cases an application may "might" work in two ownCloud versions. The ownCloud “Apps” administration only displays applications that are rated as "coreOfficial" or "stable 3rd partyApproved" for the installed instance of ownCloud. There are a large number of applications that are not displayed on the ownCloud "Apps" list but they can be independently downloaded and manually installed. Applications that have to be manually installed are usually rated as "Experimental".

Like a lot software in the Open Source world when there is a new version release (ownCloud upgrades/updates), any "plug-in" or "optional" software components written by a "third party author" may not work as expected with the new release. It takes time for the third party authors to update their software components to work with the new release. So as they say, "Patience is a virtue".

Some owncloud applications are already included (Internal App) with the base installation of the software in a "Disabled" state. Once "Enabled" they are available to current ownCloud instance users. Other applications (3rd third Party) have to be downloaded from the ownCloud Applications Store, installed, and "Enabled". The Internal App "Bookmarks will be used to demonstrate the installation of an ownCloud application.