On the Xiaomi smartphone, the one-handed mode can be activated, which makes the screen content appear smaller, making it easier to use with just one hand. when the
function is activated, we can wipe left or right from the home button to reduce the current window and slide it to the respective corner, and we can also set a size of 3.5/4.0/4.5 inches.

Android 10 (MIUI 12.0)
Step 1:  Open the  Settings
Step 2:  Tap on  Additional settings
Step 3:  Tap on  One-handed mode
Step 4:  Enable or disable  One-handed mode
Step 5:  Choose  4.5 / 4.0 / 3.5 inches
  1. Open the Settings
  2. Tap on Additional settings
  3. Tap on One-handed mode
  4. Enable or disable One-handed mode
  5. Choose 4.5 / 4.0 / 3.5 inches

Xiaomi Instructions