Before you record a professional voicemail greeting, you may want to consider the type of people who might call your home or business. That way, you can think about the information these callers might need before you compose your greeting. Most callers are familiar with how to leave a voice message, so try to avoid giving them instructions. Some things you may want to include in your greeting might be your full name, title, name of your company, and an alternate method of reaching you. If you plan to be unavailable for some time, it can be a good idea to tell your callers when you will return and give them the name and phone number of another individual to call in the event they need immediate assistance. A private voicemail box enables a person to receive telephone messages when the phone cannot be answered.
Standard greeting with phone number: "At the tone, please record your message to [phone number]."

Solution: Poor sound quality is unlikely the fault of a reliable business voicemail service that uses VoIP technology, Baldwin says. So garbled voicemails are often due to callers’ poor mobile phone reception while leaving their message—and you may just need to call them back, assuming you can figure out their phone number. But if the problem does seem to be your voicemail, make sure you’re using a business phone and voicemail service that uses VoIP and not relying on, say, your mobile phone’s voice mailbox.
On Air Recordings recommends you order professional voicemail greetings through their site, then describe the tone, approach, or voice direction you’re going for.