If you want them to leave a voicemail, tell them right from the beginning, “Please leave your name, reason your calling, and the best way to contact you.” If you want them to call you back during normal business hours, tell them, “Please call back during normal business hours.” If you want them to call back prepared for a lengthy conversation, you can say something like, “Please refer to our website’s FAQ page,” and then provide the URL. Self-service should never be underestimated.
Business owners and everyday customers know that there will be times — like the holidays — when things get busy. When you’re transparent about why you weren’t able to come to the phone, people typically understand and are much more willing to be patient with your business. If the goal is to encourage more people to leave a voicemail, your greetings have to be actionable and clearly dictate what you want the caller to do. Having a caller go to voicemail is not the end of the world; it’s going to happen, so you have to make the most of it.

Using concise and simple words in your scripting helps ensure callers can comprehend what is being said. Although a complete on-hold message can be quite lengthy, it should include concise and to the point single messages. Aim to get each message across in around 35 to 40 words. Remember, what may read great in written word doesn't necessary sound great said out aloud.
A voicemail greeting is a simple message that plays before callers leave a message. It may play either when you don’t answer or if your phone is off. A professional greeting may encourage people to leave messages, which in turn makes it easier for you to get back in touch. Keeping that communication open and efficient may lead to better business relationships. It also helps you put forth a professional image for your business.