Call Feature for Whatsapp is an Added feature App associated with Whatsapp, available for Windows8.1 Devices.
The New Call feature update will be linked and installed into the Whatsapp you are having in your Windows 8.1 Devices.
So Install this app after you complete Installation of Whatsapp.
Call Feauture for Whatsapp uses Internet connection (4G/3G/2G/EDGE or Wi-Fi, as available) to Call friends and family Whoever having WhatsApp.
Features:
Added Web Whatsapp for accessing from website also.