How do I get dynamic background on Xbox one x?

Thank you very much for your help and fast reply!

I saw on youtube a moving background and i want one how do i do it?

those are only available on Xbox series x/s I'm afraid

At this time, dynamic backgrounds are only available on the Series S/X and can't be customized. If the video you saw was done on a One, then the person doing it is doing something that violates the terms of service.

If you are on a Series S/X, when you go to settings and change your background, there's a section for dynamic backgrounds.

I like the achievement backgrounds. It would be awesome if they added dynamic backgrounds to the Series X, just like the PS4.

No. It's a dynamic background which is only available on the Series S/X