For some Windows users, it's starting to feel like Christmas in July, and Microsoft is Santa.

Just a day after the general release of Windows 10, the company has just released Office Mobile — touch-friendly versions of its Office apps for Windows tablets running Windows 10. Now anyone with those devices can use Word, Powerpoint and Excel for free, the company said in a blog post.

The Office Mobile apps are technically the same ones that will run on Windows smartphones, although Windows 10 for phones won't be released until the fall. Thanks to a Windows 10 feature called Continuum, the touch-first Office apps can adapt to multiple screen sizes form factors.

See also: How to get Windows 10 right now

The tablet-optimized apps look and feel a lot like their iPad counterparts released back in March of 2014. That means buttons and options are spaced out so they're more easily tapped. It's a big change from the congested look of the desktop apps.

The desktop Office apps won't get a refresh until fall. Why are there two sets of apps anyway? It all comes down to the legacy of Office, which has deep roots in the old Windows (Win32) ecosystem. The desktop apps need to retain much of the compatibility with old versions of Office to still be usable by many business customers and custom plug-ins.

The dual approach has a cost of adding a layer of confusion for users, though — especially on machines that blur the line between desktop and tablet, such as Microsoft's own Surface machines.

Although both sets of apps will run on any Windows 10 PC hybrid, if the device has a screen size larger than 10.1 inches, Microsoft recommends you use the desktop apps. So if you have the popular Surface Pro 3, you'll probably want to stay in the desktop camp. But if you're rocking a Dell Venue 8 Pro tablet, the new Office Mobile apps might suit you.

If you can't decide, though, your Office 365 subscription entitles you to download and install both sets of apps on one machine (though you may need to free up some space).

Ironically, Microsoft's array of Office apps are much less confusing if you don't use Windows hardware. iPad, iPhone and Android devices all have touch-friendly versions of Office apps available for free — and just one set per platform. The latest version of Office 365 is also available for the Mac.

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