With the Edge Lighting, notifications can alternatively be displayed on an active or inactive screen. In this case, a pop-up is opened at the edge of the screen. The pop-up can be personalised according to style, colour, duration and transparency. The Edge Lighting is deactivated by default on the Samsung device, but can be activated in the settings.

Note: The Edge Lighting is only available on Samsung devices that have an OLED/AMOLED display.

Android 10 | One UI 2.0
Step 1:  Open the  Settings
Step 2:  Tap on  Display
Step 3:  Tap on  Edge screen
Step 4:  Enable or disable  Edge lighting
  1. Open the Settings
  2. Tap on Display
  3. Tap on Edge screen
  4. Enable or disable Edge lighting

Samsung Instructions