You cannot embed a PDF into the content view. The Content view only supports text and simple HTML such as images and bold/italics.

One option is to embed an image of the PDF. I'm not sure if it's easy to convert a PDF into an image. If you were able to, this would embed in the content view and would be embedded in the IOK file if you sent it to someone.

Alternatively, you can use the Web view on a 32-bit Windows installation to show the PDF. You will need Acrobat Viewer installed correctly such that PDFs are viewed embedded within Internet Explorer.

In the Web view, enter the file or URL to the PDF in the address bar, such as:

file://C:\myfile.pdf
or
file:/C:\myfile.pdf
(I can't recall whether 1 or 2 slashes are needed) ...or for web URLs:
http://www.mysite.com/myfile.pdf

The problem with this approach is if you send the file to someone, they must have access to the original PDF at the same location. So if you are sending within an organisation, you can use a mounted network drive that everyone might have. Or, use a URL for a web location that the recipient will have access to.