We can set a notification tone for the created appointments or events of the calendar app on the Huawei smartphone, and in addition to the pre-installed tones, we can select custom (.mp3) tones.

Android 10 | EMUI 10.0
Step 1:  Open  Calendar
Step 2:  Open the  menu
Step 3:  Open the  Settings
Step 4:  Tap on  Notifications
Step 5:  Tap on  Sound
Step 6:  Choose a  notification sound
  1. Open Calendar
  2. Open the menu
  3. Open the Settings
  4. Tap on Notifications
  5. Tap on Sound
  6. Choose a notification sound

Huawei Instructions