Colour blind mode
For people with colour blindness, iOS and Android offer an option to better see the difference between colours. This setting can also be used by people who, for example, find a yellower screen light more pleasant to read on their tablet or telephone.
On iOS, this accessibility feature is called Colour Filters. It is possible to choose shades of gray or other filters that can also be set in intensity.
On Android, adjusting the colours on the screen is called Colour Correction. Android offers fewer colour filters than iOS. It is, however, possible to pin a shortcut for colour correction on the screen.
The metric for colour blind mode is not available on iOS at the moment.
use colour blind mode on Android.
Incidentally, both iOS and Android also offer the option to completely invert colours.