As long as you have access to a wireless data service and a compatible device, you can use VoIP right away.
VoIP Advantages & Disadvantages – The Good and the Bad
However, there are a few things you need to keep in mind that make VoIP different from regular phone calls.
Sending your vote over the internet is a great achievement. There are some great advantages to it, but there are also some disadvantages.
To make free calls with your mobile device (phone, tablet, PC, etc.), you will need a connection to some type of data service. Some mobile network technologies work everywhere, but others, such as Wi-Fi, have extremely limited range.