Using Google Docs you can display documents online. Following are the steps
1. Upload the file to be displayed to Google Docs.

2. Open the file in Google Docs. And click on Share button,

3. Now click on Get shareable link.

4. Now copy the link and click Done.

5. Use iframe and set the URL in the iframe.
<iframe frameborder="0" src="https://docs.google.com/spreadsheets/d/13U_fwglOdiPg1_KP8WHIk1Ezw9QMFamlAqBmbtItJ0c/edit?usp=sharing"
width="600" height="300">
Demo