Last year Amazon added the Alexa calling feature to Echo devices, essentially turning your smart speaker into a phone. That meant you could use your Echo to call other Echos without having to pay anything. Echos in North America could even call mobile and landline numbers, as if it were an actual proper phone. Today Amazon is expanding the functionality to new devices, bringing Alexa calling to tablets running Android, iOS, and Amazon's own FireOS.
That turns the Alexa app into a VoIP service that lets you keep in touch with anyone that owns an Echo, Echo Dot, Echo Spot, Echo Show, or any other device running the Alexa app. That means your tablet is now capable of using the Alexa Calling feature to send messages, or make voice and video calls. Obviously you can't make a video call to a regular Echo, but that should be obvious seeing as how it doesn't have a camera.
If you're running an Alexa compatible Fire device all you have to do is tap the home button and ask Alexa to make a call for you. Android and iOS have extra steps, forcing you to manually open the Alexa app before you can talk to the virtual assistant, but the basics are the same. Ask, and Alexa shall give.
To set everything up you need to make sure you have the latest version of the Alexa app, which will verify your phone number and import your contacts. After that you're good to go, and can call or message all your friends. Well you could do that before, but now you can talk to them through their Amazon-brand speaker if you really want to.
You can read more about Alexa Calling over on Amazon's website.