By default, the Xiaomi smartphone's device name is the model name, which is displayed instead of the MAC address for Bluetooth and Hotspot connections, for example, to help you assign the device more quickly. The device can be renamed as desired.

Android 10 (MIUI 12.0)
Step 1:  Open the  Settings
Step 2:  Tap on  About phone
Step 3:  Tap on  Device name
Step 4:  Enter a  name  and tap  Save
  1. Open the Settings
  2. Tap on About phone
  3. Tap on Device name
  4. Enter a name and tap Save

Xiaomi Instructions