This page contains information about Skype for Business Mobile
Notes:
Skype for Business Mobile may use cellular minutes and/or cellular data: Skype for Business uses WiFi by default for calls and video, but Skype for Business' Simultaneous Ring and Forwarding features may use your cellular minutes and data plan if you are out of WiFi range and answer a call using the mobile app.
Additional Information from Microsoft
Visit the Skype for Business Mobile app pages to learn more.