Contact your carrier and ask them to disable voicemail on your line
Dial your carrier’s voicemail deactivation code, if available
Turn on call forwarding to another number so calls do not reach voicemail
Use Do Not Disturb or Focus mode to silence calls without disabling voicemail
Delete or clear your voicemail greeting if your carrier allows it
Remove voicemail access from your iPhone only if your carrier supports that option
Check your carrier account settings or app for voicemail controls
Ask your carrier to disable visual voicemail and voicemail inbox access