The list of apps available to a customer depends on various factors, such as the service plan settings, the Application Vault configuration, and so on. Moreover, service providers are able to forbid accessing apps for all Plesk users. If you do not adjust the app availability, your customers will see all apps from Application Catalog and all apps you uploaded to the Vault.
To view the list of apps available to a certain customer, go to the Applications section > All Available Applications. Before an app becomes available in the app list of a certain customer, it passes through a series of filters. The app is filtered on the following levels:
Plesk lets you toggle the availability of APS packages you have uploaded to the Vault. Note that this works only for your own packages: There is no way to control the availability of apps downloaded from the Catalog. Learn more about apps management in the Managing Apps with the Application Vault section.
Plesk allows you to specify what apps to include in a certain service plan. The filter affects all customers with this service plan.
If you want to select the apps available to a particular customer, update the apps list in the respective subscription.
The resulting app list is available to your customers.