elastoplastic775 when I reinstall, my login information etc is saved.
On GOS?
So, depending on the application, on "standard" android the "login information" may simply be a phone number or Google account that is by default accessible to apps, so it's not the app's data per se. The app sees a user with such phone number or Google account and that's it, you're "found".
On GOS, Apps are deleted altogether with their data, unless you specifically ask to keep data after uninstalling