Communicate in your favorite instant messenger using a computer could be before, but only through the web version or third-party applications. Now it can already be done in the official client. Unfortunately, it can not be completely autonomous: unlike Telegram and other competitors, to authenticate the desktop WhatsApp, you still need a smartphone that will need to scan the QR code.
The application differs from the mobile version, except that there are no calls. Otherwise, the possibilities are completely analogous: chats, groups, sending media files and documents, voice messages. The interface is not overloaded, has the minimum number of elements and is quite convenient, you can see everything yourself.
The application is available on Mac and Windows, and you can download it from the official site. The only thing that can upset is the lack of support for Windows 7: it claims compatibility only with Windows 8, 8.1 and 10. On Mac desktop WhatsApp works from OS X version 10.9.