If Quick calling is activated on your Huawei device, you can make a call while the display is on standby. To start a quick call, you need to press and hold the volume down key and say the name of the contact you want to call.

Android 10 | EMUI 10.0
Step 1:  Open the  Phone App
Step 2:  Open the  menu
Step 3:  Open the settings
Step 4:  Tap on  Voice control
Step 5:  Tap on  Quick calling
Step 6:  Activate or deactivate  Quick calling
  1. Open the Phone App
  2. Open the menu
  3. Open the settings
  4. Tap on Voice control
  5. Tap on Quick calling
  6. Activate or deactivate Quick calling

Huawei Instructions