Personal data should generally not be stored, unless it is necessary for delivering a specific service.

The website should not store any personal data, since it is not necessary for delivering the service of the website.

The apps might store personal data necessary for them to work, on the device where the app is installed, since it is necessary to store some data to deliver the service of some apps.

Deleting the app, should also delete the personal data stored on the device.

No personal data should be transfered or stored centrally.