Dual apps are app copies that can be used separately with another account, which means that we can use dual messengers, such as the WhatsApp or Facebook app, with two different accounts because one app copy is created on the home screen and each one works on its own.

Android 10 (MIUI 12.0)
Step 1:  Open the  Settings
Step 2:  Tap on  Apps
Step 3:  Tap on  Dual apps
Step 4:  Enable or disable a  dual app
  1. Open the Settings
  2. Tap on Apps
  3. Tap on Dual apps
  4. Enable or disable a dual app

Xiaomi Instructions