Besides creating an audio file in the right format (Adaptive Multi-Rate), you also need to trick the iPhone to upload your new greeting to the AT&T servers:
Open Phone → Make sure you are on Keypad → Press and hold the number 1 for a few seconds. It will call your voicemail; You can check your voicemails here. 3. Force close and reopen the Phone app. To force close Phone, on iPhone X and later swipe up until you see the apps in task view, then swipe up again on Phone.

The professional voicemail greetings is the cornerstone of any good business. Not every voicemail recording is relevant to every situation. This guide is going to demonstrate some of the specific custom voicemail greeting examples for doctors, dentist, real estate agent, lawyers and other professionals. A doctor’s practice typically either has a secretary or the doctor themselves to take calls. It’s vital that you have a different voicemail based on the area of the practice the patient is calling. The information differs, but the tone of voice remains the same. It should be warm yet professional because many patients will be distressed or worried about potential symptoms and conditions.
Voicemails don’t necessarily have to be monotonous or extremely jazzy or funky. What you’re looking for is a balance between the two. Whenever I call someone and their voicemail greeting is playing, it tells me a lot about who they are, as a person. Which is why, you’ve got to put a little bit of “you” when it comes to voicemail. And the best part about all of this is, since you couldn’t come to the phone, at least the callers are having a good time listening to the message.