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.
The most engaging messages are slightly unique in nature. They combine a mix of clever scripting and music. Slight humour is often used to promote a product or service and is usually quite effective. It's also very important to choose both the written and spoken tone that appeals to the characteristics of your audience. If your target market is the younger generation, a script that includes slang words and is quite laid back would be an excellent choice. If your target market is primarily business professionals, then a more articulate choice of words would be more suitable.

Finally, you can mention your name in the recording. This is a good idea if your calls are still coming into a cell phone. If you’re on a first name basis with all your customers, it adds that extra personal touch to include your name in the voicemail. If you’re not on a first name basis, but you’d like to be, then use your name to encourage customers to use it!
These are just a few ideas to get the gears turning. These are simple examples, but don’t be afraid to show a little personality.