To install the CRM for tablets app on your tablet, click the link in the following table for your tablet. The link will take you to the app on your tablet's app store.
The Windows 8.1 app only works on Windows 8.1, but either the Windows 8 or the Windows 8.1 app works on Windows 8.1 tablets.
If your organization has an on-premises deployment of CRM, you need to make sure that your organization is ready for you to install the Windows 8.1 app before you install it. More information: Troubleshoot a CRM for Windows 8.1 app start-up error