Samsung Galaxy S21 Ultra 5G
Android 11.0
1 Find "Voicemail number"
Press the phone icon.
Press the menu icon.
Press Settings.
Press Voicemail.
Press Voicemail number below the required SIM.
2 Save voicemail number
Key in 707 and press OK.
707
3 Return to the home screen
Press the Home key to return to the home screen.