We can place one or more stored contacts to the Xiaomi device's home screen, making it even faster to dial important or frequently dialed contacts. For example, we can start a call with just two taps by dialing the contact and tapping their phone number.
We also have the option to set up a direct dial. Then the contact with the selected phone number is called directly.

Android 10 (MIUI 12.0)
Step 1:  Open the  Contacts app
Step 2:  Choose a  contact
Step 3:  Open the  menu
Step 4:  Tap on  Place on Home screen
Step 5:  Choose  View contact  or  Direct dial
Step 6:  Tap on  OK
  1. Open the Contacts app
  2. Choose a contact
  3. Open the menu
  4. Tap on Place on Home screen
  5. Choose View contact or Direct dial
  6. Tap on OK

Xiaomi Instructions