I'm not sure what you are asking because I don't recognize the term 'home bar'. Could you provide a screen shot?
That aside: The 'IOS' is not an Adobe item. It's an Apple operating system.
Google it. Home bar is a new feature on iPhone X. Apple left it to app developers to enable the auto-hide feature. I am writing here so that somebody from Adobe might take notice (they left these forums as a single recourse for those willing to report some issues, there is no other way to reach Adobe.
Why are you replying to a thread if you have no idea of the topic?
Why? Because it's a learning process. I barely even notice that tiny, little, thin white line at the bottom of my phone view port.
What I learned is some users view it as a huge issue.
My bet is that Auto Hide feature is a very long way down on the Adobe to-do list.
I am glad that you barely notice the tiny line (which is not so tiny after all), but I bet your Samsung AMOLED screen does notice it very well! It will be the first spot to show permanent burn-out.
Secondly, Apple went to great lengths to remove all obstructions and distractions from the front panel of the iPhone, in order to maximise screen real estate. Now to put a permanent home bar instead of removed home button seems silly to say the least. They might have just kept the home button and never bothered to catch up with all the Samsung infinity displays!
The home bar is plain pesky and obtrusive, especially in not-yet optimised apps that have full screen media view modes (like photo, video and game apps)! Last time I checked it was there stuck all the time in Apple's own iBooks. Best recipe for AMOLED burnout is to keep a bright line burning on the same spot while you read books for hours!
Guess I'm lucky. I use that little scroll bar, It's an excellent app switcher.
Well, you don't need the bar to use the app switching feature. Just drag the bottom of the screen to switch apps!
Yep! Drag the bottom of the screen RIGHT WHERE THE WHITE BAR IS.
But, it guess, your definition (words used) are better than mine.
Fortunately there is a pretty easy workaround that allows you to disable & hide the home bar while using any app, without jailbreaking your phone: