Normally, Samsung devices display apps in full screen, meaning that the apps are aligned to the full width/length of the screen. However, stretching the screen content can sometimes cause problems, and we cannot disable full screen display. We can only instruct the Samsung device to explicitly select full screen mode so that no black areas appear around the app.

Note: If the notch or camera detail is disturbing, it can also be hidden.

Android 10 (One UI 2.0)
Step 1:  Open the  Settings
Step 2:  Tap on  Display
Step 3:  Tap on  Full screen apps
Step 4:  Tap on desired  App
Step 5:  Tap on  Full screen
  1. Open the Settings
  2. Tap on Display
  3. Tap on Full screen apps
  4. Tap on desired App
  5. Tap on Full screen

Samsung Instructions