Google (Free)
Google Voice is a communication app that lets you make calls and receive messages. It comes with a phone number and voicemail, and you can sync all data across other devices. These services are only available in the US.
This app doesn’t do much more than your regular mobile carrier. It wants to give you a phone number, but you still have to link it to yours. In other words, you will need a phone number to get another one. Even if you decide to go on, sometimes Google would fail to verify your number.
Call and text
Takes over your device
The number you get is free, but the services will rely on your current mobile plan. You do have the option of wifi calling, but almost any social app out there can do that. Worse, the app will override your current number whenever you make/receive a call. It will show up as the Google Voice digits and not your original one.
You can block calls and texts with GV, but only if you use the app’s settings. Otherwise, it will ignore whatever settings you have on your phone. It somehow can bypass the do not disturb mode and let through a call.
International calling
GV runs in the background draining your battery and RAM in the process. One thing it does offer is low international rates. Getting a mobile plan can be expensive and may cover the countries you don’t need. With GV you can select the area you want to connect to.