On SkyDrive, Outlook.com, and Office 365 you can view PDF files using the Word Web App. PDFs attached to mail or stored in SkyDrive are quickly viewable in the browser regardless of device or whether you have PDF viewing software installed.
Additionally, for SkyDrive you can convert PDFs to editable Word documents. This allows you to “release” the text in PDFs without requiring PDF editing software. Please note that the conversion does not change the PDF itself. Converting creates an entirely new file. Also, depending on the content of the original PDF, the formatting of a converted Word document may vary from the original.
On SkyDrive, just clicking a PDF will view the file in Word Web App. If you prefer to download the file to display in your current PDF viewer, right click and select Download.
With Outlook.com, select “View online” at the bottom of the PDF attachment icon. To download, click the icon anywhere else.
Outlook Web App (Exchange)
Using Outlook Web App, hover over the PDF attachment icon to reveal the Preview link. Click it to use Word Web App. To download, click the icon.
Download the PDF
From within the Word Web App you can also download the PDF by clicking “Download” in the toolbar at the top of the document.
Source: Office Blog