Voicemails help in conveying messages from the caller when the concerned person is not available for attending the call. It has become a vital tool in telecommunication as the person receives the information instantly after accessing his phone. Thus voicemails allow us to stay connected with people both at personal and professional level.
Website: https://www.onsip.com/voip-resources/smb-tips/after-hours-voicemail-and-auto-attendant-greetings

Consider for a moment how your phone is currently being answered. Professional courtesy is quite often not the standard for many college students. An abrupt "Yeah!" could be listed among the more courteous greetings. The more outrageous remarks will often buy you a major black mark in the professionalism category—even if it was your roommate answering your phone and acting crazy. A simple "This is ____" is always a pleasant change for a college student call. Make the change today, before the next (or first) employer phone call. If you have a landline, you should also encourage your roommate to do the same.
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.