Hi All :
Online Viewers enable users to use a web browser to view Excel, PowerPoint and Word files that are stored on web servers or shared folders in an organization. Users can conveniently view Office files in a web browser without having to open a separate application. In addition, Online Viewers do not require Office 2013 to be installed on users’ computers. Online Viewers also generate the code that is required to link or embed the URL inside a webpage. You can use Online Viewers within your Intranet, or on the Internet.
Office Web Apps Server provides a page at the address http://OfficeWebAppsServername/op/generate.aspx that you can use to generate links to publicly available documents that have UNC or URL addresses. When a user selects a generated URL, Online Viewers enable Office Web Apps Server to get the file from its location and then render it by using Office Web Apps. The user can view the Word, Excel, or PowerPoint file in a browser with Office features intact. Formatting and layout in Word documents are preserved, data in Excel workbooks can be filtered and sorted, and animations play in PowerPoint presentations. However, be aware that Online Viewers allow users to view but not edit files, and Online Viewers can't open any files that require authentication.
This blog post neither introduce how to install a Office Web Apps Server 2013 environment nor how to configure a certificate. These part you can refer my previous blogs. I am assume you have completed these phase.
Now open the Windows PowerShell cmdlets, using Set-OfficeWebAppsFarm - OpenFromUrlEnabled to enable URL opening files. When Online Viewers are turned on (set to True by using OpenFromUrlEnabled), this parameter turns on or off the ability for Online Viewers to display files in UNC paths. By default, this parameter is set to True, but make sure OpenFromUrlEnabled is also set to True before you enable opening files from UNC paths. We recommend you set this parameter to False if you have set up Office Web Apps Server to connect to the Internet.
Then open online viewers generate website : https://<OWA's FQDN>/op/generate.aspx , enter the file UNC address and click Create Link:
Then click Test this link, will online viewing the file:
Also you can open the PDF file:
Powerpoint Web App: