Google Voice is a telephone service that can unify communication channels, allowing multiple phones to ring simultaneously through a single, toll-free phone number that works like most other phone numbers. When a call comes in, you have several options for handling this communication.

At its core, Google Voice is not a VoIP service like Skype, but it does use VoIP technology over the Internet to route some of its calls, provide cheap international calling, free local calling, and provide the many features it is known for.

Google Voice provides a phone number. This will forward incoming calls to a phone of your choice: your landline, smartphone, or another phone.

Another way to use Google Voice is to port your primary phone number to this service. This allows you to use your existing number as your Google number. However, this feature does have a few drawbacks.