You no longer need to hang around an Echo speaker to make free calls and messages with Alexa. As of now, you can use Alexa to place calls (including video calls) and send messages from Android tablets, iPads and of course Amazon’s own Fire models. How easy it is depends on the device. It’s easiest on the Fire HD 10, where you only have to ask Alexa to get in touch; other Alexa-ready Fire tablets require that you tap the home button first. And for everyone else, you’ll have to open the Alexa app.

Source: Amazon (1), (2)