Hi @Nuricik, let me see if I can help out here.
I have translated your question to English as this is an International forum, please post any replies in English and it will be easier for me and other users to assist you.
Fullscreen mode, also known as hiding the navigation bar at the bottom of the screen and the notification bar at the top, can be enabled in the app code, and cannot be controlled by the UI settings of the device. Depending on the app or content, the proper fullscreen mode will be activated automatically.
I hope that answered your question. Feel free to return if I have misinterpreted your question in any way! 
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