Create and edit documents
With Office Web Apps, you can create and edit Microsoft Word, Excel, PowerPoint, and OneNote documents online—even if you don't have Office installed on your computer. So if you created a party invitation using Word on your work computer and want to edit it from a different computer which doesn't have Word installed, no problem! You can edit your invitation online, and all your original formatting is still there.
Switch between the web and the program
When working in an Office Web App, you can seamlessly switch between Office Web Apps and Microsoft Office programs on your desktop. For example, you might want to make changes to your file that require the feature-rich version of the Office program on your desktop. If this is the case, you can transition to the Office desktop program directly from the corresponding Office Web App with just a single click.
Upload your documents
Use Windows Live SkyDrive to upload and store Office documents and other files securely online, from wherever you happen to be. While working in Microsoft Office 2010, you can also save files directly to SkyDrive for anywhere access.
With Office Web Apps, you can print your Microsoft Office documents no matter where you are or what type of computer or browser you're using.
Works on your phone
Office Web Apps works on popular smartphones, such as the Windows Phone and iPhone, so you can access your files and stay productive wherever you are.
You can view Microsoft Office files on Windows Live SkyDrive when you're on the go. Get high-quality previews of Word and PowerPoint files in the browser of your smartphone. Some smart phones also allow you to download Office files directly to your phone and work with them there.