Open the Phone app
Tap Voicemail
If your carrier supports it, contact your carrier to disable voicemail service
Dial your carrier’s voicemail deactivation code if available
Turn off Live Voicemail in Settings
Go to Settings
Tap Phone
Tap Live Voicemail
Turn Live Voicemail off
Set Call Forwarding to another number if you want calls to bypass voicemail
Go to Settings
Tap Phone
Tap Call Forwarding
Turn Call Forwarding on
Enter the forwarding number
Ask your carrier to remove voicemail from your line if you want it fully disabled