Hi together,
on all websites if you open it for the first time, there is a question to allow
- All cookies
- just needed
- No cookies
can someone tell me how to realize such stuff?
That’s not on all websites, just some. It’s purely custom code, there’s no Cake plugin I’m aware of that does this for you.
If you don’t know what GDPR is you have a lot to learn 
All I can say is, that its mainly a client side (JS) thing you need to implement if you use someting like Google Analytics, Facebook Pixel or anything, that tracks your users.
Something like this might help you GitHub - AmauriC/tarteaucitron.js: RGPD friendly cookie manager