Summarize:

You're able to do that by installing a particular app. In order to download the correct app, search the Internet for the model of your phone along with the "QR reader". This will automatically download the office app onto your phone.
Make sure your phone can scan a QR code with its camera. Enter the Android Market or Kingsoft official website and find the QR code for the office app. Use the QR reader installed on your phone to scan the code. After the app has downloaded, you're able to install it simply by selecting it.