I have an S10+ which has a circular, moderately transparent floating menu permanently on the screen which can be clicked for several uses. The two most useful are volume adjustment and an immediate screenshot which I use all the time. I had presumed that this was also on other family members" Samsung mobiles but apparently not, and no one has even heard of such a thing. Can find nothing in the manual or settings.
Can anyone tell me a) what this is called? and b) why I have it but not others? Thanks in advance!