Microsoft let slip back in June that the version of Microsoft Office 2013 that would be available to Windows RT tablets and PC customers would be a "preview" test-build. In blog post yesterday, Microsoft confirmed that information and added a few more particulars about the Office Home & Student 2013 RT bundle that will be available to those with ARM-based Windows devices.
Office 2013 RT won't be available for purchase as a separate product. It will be "included" with ARM-based Windows RT tablets and PCs and will function as a desktop app, meaning it won't be available through the Windows Store.
The final version of Office Home & Student 2013 RT will be available to customers between early November through January 2013, with exact timing depending on language, Microsoft officials said. Those who buy Windows RT devices before the final is out will get the preview build, which will be updated to final for free via Windows Update.
Read more at source:
Microsoft plans to deliver Office 2013 RT starting in November | Microsoft - CNET News