When you create a professional voicemail greeting, it can be a good idea to think about what your callers might want to know. After doing so, you can make a list of points to cover in your voice message; it might also be a good idea to write out the entire greeting on a piece of paper. The ideal message should be somewhere between 10 and 20 seconds, so you may want to time yourself repeating your message before you record it. After composing your telephone message, it can be a good idea to get a second opinion of this greeting so you can make sure it sounds professional. Writing down a voicemail greeting helps prevent mistakes when recording it.
For example, a message like, “Hi, this is Jim. You know what to do.” Well, not everyone is going to know what to do—i.e. they won’t leave you inclusive information. Additionally, they may not leave you a message at all. Aside from this, humor can again be detrimental to your message, this time lending itself to ambiguity and costing you clarity. For example, if a message read, “Hi this is Jim, sorry I can’t answer your call right now. Please leave your name and number and I’ll call you as soon as I can, but you already knew that right? Do I need to tell you what to do?” This is worse than the previous example as this is confusing and can also come across as rude and unprofessional. Complicating a greeting with phrasing like this is sure to cause some harm. e. Ignoring Personality & Identity: Don’t use computer generated greetings. Some users leave default messages (‘you’ve reached the voicemail box of 777-777-777, please leave a message). Believe it or not, even this can cause problems. Callers may be unsure if the voicemail box belongs to you; therefore, they don’t leave a message. Also, some may even be uncomfortable leaving information through a message in a nameless voice message box. As such, impersonalization can cause ambiguity, which again can hurt the effectiveness of your voice message system. This doesn’t mean you have to make an elaborate greeting if you don’t want to, just insert your voice and name so at least callers know they’re calling the right person.

You can also upload an unavailable greeting using the OnSIP app. After logging in, click on the Voicemail Settings gear icon at the far right. Make sure that the Custom Greeting is toggled to "on." You will then see an option to upload a .wav file of your choice. This recording will serve as your unavailable message.
20. “Hey there! Thanks for calling [company]. We are unable to answer the phone right now but will get back to you right after the holidays. We hope it’s not an emergency, but if so, we’ve got you covered. Contact us at [company email/other support lines] and we’ll get back to you ASAP. Please be sure to leave your name, phone number, and a brief message to let us know the reason for your call. Thank you and have a great day.” Available even during holiday emergencies? Let your callers know via your voicemail greeting.