Once you move to Skype for Business Server 2019 you'll be automatically upgraded to Cloud voicemail. Since Cloud Voicemail is a part of Skype for Business Online and Teams Online you'll need to enable your Skype Online License in your office 365 Tenant. Just go into your use licensing and flip the switch, and Cloud Voicemail will be available!
I have a confession to make: I haven’t recorded a new voicemail greeting since 2014. In the past four years, I (hopefully) have become more articulate, poised, and self-assured. But hear my voicemail recording, and you’d think I was still new to the work world, a little unsure of myself — and probably not an authority. Obviously I need toupdate it. And if you haven’t changed your voicemail greeting in over a year, you’re likely in the same boat. After all, a professional voicemail recording boosts your credibility, makes you seem more competent, and encourages whoever’s listening to it to continue the relationship. A relatively unprofessional one — like mine, for instance — does the opposite: It encourages prospects, recruiters, and potential connections to run in the other direction. With that in mind, I’ve written 18 unique voicemail greetings for every situation. Pick your favorite, practice a few times, then record your new voicemail.

Of course, yours may need more details. But, even if you’re changing your outgoing message every day, it should only be a slight variation from a standard greeting.
Virtual Receptionist allows all calls to be answered automatically - 24/7/365. Set up a customizable greetings that can route your callers to specific departments or extensions, and you can even give your Virtual Receptionist its own office hours with time-of-day scheduling, ensuring your customers hear the right greeting at the right time. Combine with other advanced features like rollover hunting and call queue with hold music that makes the wait enjoyable to ensure you never miss a call again.