By using “Content Editor Web part” we can display PDF File in SharePoint site.
1.Add a “Content Editor Web part” to your SharePoint page.
2.Click on the “Open the Tool Pane”, click on “Source Editor” to place the HTML source.
3.Place the following piece of code in to the Source Editor and click ok
<embed height=”500px” width=”500px”
src=”http://siteurl/test.pdf” type=”application/pdf”>