Samsung Galaxy Tab S 10.5
1 Find "Voicemail number"
Press the menu icon.
Press Phone.
Press the menu icon.
Press Call settings.
Press Voicemail.
Press Voicemail settings.
Press Voicemail number.
2 Save voicemail number
Key in 707 and press OK.
3 Return to the home screen
Press the Home key to return to the home screen.