If you have received the Apple iPhone 8 with a new mobile contract or if you are still using your mailbox, you may want to deactivate it. With your mailbox deactivated, your iPhone 8 will ring until you answer the call or the caller cancels it. To switch off the voicemail on iPhone 8, proceed as follows:
From your home screen, open the phone app that you use to make calls. You must now change to the numeric field and enter the following GSM network code:
Confirm the network code by pressing the call button (green handset). What's this code doing? This enables you to deactivate all call forwarding that is stored with your mobile service provider such as At&T, T-Mobile Verizon etc. Since the mailbox is also a call forwarding, it is now deactivated.
From now on, a call received on your Apple iPhone 8 will no longer be forwarded to your mailbox, but will remain on the line until you answer or hang up the call. You have successfully deactivated the answering machine with Apple iPhone 8.