Open the Phone app
Tap Voicemail
Delete any existing voicemail messages
Contact your carrier and ask them to disable voicemail
Turn on Call Forwarding to another number if your carrier supports it
Set up a call forwarding or no-answer rule through your carrier
Use Do Not Disturb or Focus mode to silence calls without sending them to voicemail
Disable voicemail notifications in Settings
Ask your carrier to remove voicemail from your line entirely
If needed, reset your network settings after carrier changes