On the Samsung device, we can change the sound of the timer. We can use either the standard timer tones or a custom tone. The timer tone sounds when the time has elapsed.

Android 10 (One UI 2.0)
Step 1:  Open the  Clock -App
Step 2:  Open the  menu
Step 3:  Open the  Settings
Step 4:  Tap on  Sound
Step 5:  Choose desired  Timer Sound
  1. Open the Clock-App
  2. Open the menu
  3. Open the Settings
  4. Tap on Sound
  5. Choose desired Timer Sound

Samsung Instructions