A professional voicemail should be short and succinct. Simply introduce your company, ask the caller to leave their information, and let the caller know when to expect a callback. Once you record your greeting, you can easily upload it into the OpenPhone app. Simply go to your phone number’s settings, then choose to record a greeting, upload an mp3 file, or use text-to-speech.
Please note that if you record an unavailable greeting, it will be used instead of the default message with your name recording.

I had the same issue and was able to figure it out. When in phone mode, press and hold the 1. This will dial into your voicemail system the "old school" way. Here you need to follow the prompts to set up your greeting for the first time. You can change other settings here as well. Once you have created an outgoing voicemail message, go to the voicemail menu on the iphone, choose custom and press play. You should here the greeting. Press save to verify it. Jun 30, 2007 6:09 PM View answer in context first Page 1 of 1 Page 1/1 last User profile for user: Cameron Jewell Cameron Jewell User level: Level 2 (460 points) Jun 30, 2007 4:52 PM in response to Dave Low In response to Dave Low
With Visual Voicemail, you can see a list of your messages and choose which ones to listen to or delete. Learn how to set up and transfer your existing voicemail. Create a voicemail password, then tap Done. Enter your password again to confirm it, then tap Done. Select Custom or Default. If you choose Custom, you can record a new greeting. Go to the Phone app, then tap the Voicemail tab. Tap Set Up Now. Enter your password,* then tap done. Record a custom greeting or use the default greeting, then tap Save.