For a VoIP system to work, it needs a means of routing calls between users or to the outside world. In a cloud based system, a virtual PBX does that job. What that means to you is that the provider is running a large PBX operation in a data center somewhere, and slicing off a little of it to dedicate to your organization in exchange for your money. You're essentially sharing a large PBX with that provider's other customers, but because these companies use multi-tenant segmentation, your PBX will appear dedicated to you. This engine will take care of routing calls on your VoIP network.
However, VoIP traffic to and from the on-premises systems can often also be sent over secure private links. Examples include personal VPN, site-to-site VPN, private networks such as MPLS and SD-WAN, or via private SBCs (Session Border Controllers). While exceptions and private peering options do exist, it is generally uncommon for those private connectivity methods to be provided by Hosted or Cloud VoIP providers.
For the business that needs better tools for allowing collaboration between employees, 8×8 has some strong features. Employees individually can host conference calls, either audio and video calls. They can set up online chats with each other, making it easier to stay in communication, even when they’re out in the field. 8×8 also provides integration with other collaborative tools you may already be using, like Salesforce, Microsoft Office 365, or Google G Suite.
VoIP service simply enables your phone calls to be transmitted and received over your home Internet connection instead of your telephone landline. This is perhaps why some people refer to the service as being an Internet phone service or broadband phone service. This does mean though that you need a high speed Internet service to be able to use VoIP for your phone service.