What are virtual numbers?

Virtual numbers work over the internet and exist in the cloud.

Unlike traditional fixed telephone lines they aren’t tied to a particular telephone exchange so, whatever the number, whatever its prefix, it can be used anywhere in the world. 

 A virtual phone number works over the internet, exists everywhere - so can be used anywhere. 

In terms of making and taking calls they feel like any other number. But in practice they are significantly more flexible and versatile than fixed line numbers.