WhatsApp isn't directly available on Firefox OS, but you can still use a WhatsApp client on your device or chat with friends using Facebook or LINE.
The Marketplace is a store that features apps designed for any device that runs Firefox OS, Firefox for Android or Firefox desktop.
This article covers the basic features of Firefox OS - apps, messaging, contacts, music and more. It also links to articles that you'll want to explore later.
The Firefox Marketplace has apps designed for your Firefox OS device. We'll show you how to find and install them.