If you have seen them, the recent samsung phones (from the S8 to the latest mobiles) have had a different UI / OS look to the previous mobiles (S7 and lower).
If you were wondering why you can't see this, it may be that your phone is on a old software update or that the hardware in the mobile cannot cope with the new software package.
If you have a new phone (that you got in the past year) ensure that you are on the latest software update. If you have an older phone (from two years ago or further) then make that you are on the latest software, but there is a chance that you don't have a phone that can cope with the software.
(A good representation of this is to check if you are on Android 8.0.0 or lower / higher.)
Hope that this helps. If you have any other issues, feel free to comment on this community post. If this did help, please consider supporting it.