1. An Azure account is required to enter the Microsoft Business Store (https://businessstore.microsoft.com)
2. Within the store, you search for apps. If the offline license is available, you can “Purchase" or "Buy" (even if it's free) the app.
3. Go to your purchases apps –> “Manage”
4. Select the app
5. Choose your platform and download the “appx” files
6. Also download the appx packages that are required additionally (required frameworks)
7. With a powershell command, you can install the appx files on the PC (https://technet.microsoft.com/en-us/library/hh856048.aspx)
Please contact your Microsoft Technical Account Manager (TAM) or Microsoft Services Technician for further support of Microsoft Store applications and offline installations.