The basic rule of thumb is that callers should hear one of two things when they first connect with your voicemail — either an apology for not being able to answer the call or a “thank you” for having called. You can do both if you prefer, but keep it short and to the point.
Many of our users don’t need calls routed to their phone, they just want a good virtual voicemail system. We can do that, too. Just set up your VirtualPBX account with multiple voicemail boxes for each user or purpose you need. Furthermore, we can route calls directly to voicemail, without ringing a phone first.

Expanding on the simple approach above, let the caller know who they've reached. This will not only eliminate people leaving voicemails by mistake, but it will reassure the caller that they have called the number they intended.
Your voicemail greeting can make a positive or negative impression on people. By considering your target audience and tone, you should be able to keep it positive. Length: Don’t make people wait minutes to leave a message. Apologies: If people expect your to be available, apologize for missing their call. Set expectations: Let people know when they may receive a callback, but be realistic. Accuracy: If you change your voicemail for things like holidays, be sure to update it when needed. How do You Set Up a Business Voicemail?