"Colour inversion" reverses all colours on the Samsung device, white becomes black, green becomes light blue, etc. In addition to the system, it also reverses the colours of media (photos, videos, etc.).

Android 10 (One UI 2.0)
Step 1:  Open the  Settings
Step 2:  Tap on  Accessibility
Step 3:  Tap on  Visibility enhancements
Step 4:  Enable or disable  Colour Inversion
  1. Open the Settings
  2. Tap on Accessibility
  3. Tap on Visibility enhancements
  4. Enable or disable Colour Inversion

Samsung Instructions