Just like the importance of conducting yourself professionally in person and over email, you want to make sure that if an employer is trying to contact you, that they receive a professional greeting, even if you aren’t able to answer the phone right away.
Your voicemail should be very specific. It should be short and urgent. Use word's like "need", "should", "must" , or "have to" to create a sense of urgency. For example, say something like, "We need to discuss..." or "We should talk about..."

To create the best recordings takes the right equipment and the best talents for voiceovers. Thankfully, there are professional voice recording providers who can supply the tech and the talent to create high-quality voiceover for professional voicemail greetings and more with ease. Learn more about creating professional voice recordings today! Topics: Voicemail Messages
The alternative is simple: Provide in your voice message a phone number and refer the caller to an assistant, a colleague, a cell number—any way of expediting their quest. Help your caller to reach someone who can, in your absence, be helpful and succeed in keeping the business. And remember to update your voicemail message when appropriate.