Skype for Business is available as app for Android, iOS and Windows phones.
The app is free, and you download and install it from your phone's app store.
Once installed, you simply sign in with the username and password that you use for Skype for Business on your computer.
Please note. TDC Business cannot offer any type of technical support on these apps, and we do not accept any responsibility for changes or missing functionality, they are updated directly from Microsoft.