Voicemail greetings can be accessed and managed by dialing *97, then taking the following steps: Select Advanced Options #5 To record a greeting Press 1 Choose a greeting between 1 and 9 (this is the greeting you want to record) Choose a greeting (this option lets you choose your default greeting. The default greeting is what plays if an extension dials you directly or if a call is transferred to your voicemail) mangovoice.com Sign in How to Change Voicemail on iPhone 12Pro Max, XR, 11(Pro Max), XS Max (Voicemail Greetings Message)
If you’ve already created a custom voicemail on your iPhone, you can tap Play to see how your voicemail sounds. If you’re interested in creating a new message, tap the Custom button. From here, you can start recording your message by tapping Record and tapping Stop whenever you’re finished. Once you’re finished recording, tap on Play to make sure the message comes across as you’d like and hit Save (in the upper right) to save it as your voicemail.

Website: https://community.verizon.com/t5/My-Verizon/How-do-I-change-my-voicemail-to-the-automated-greeting/td-p/1047569
1. Tap the fixed key with the envelope graphic, or dial the phone’s phone number.