to commonly asked questions.

How can I open this attachement?

This pdf came in a secure email but I can’t open it by clicking. Can you help me find it?

Not sure what application you're currently using to view this mail but first you should try simply dragging it to the desktop. If this is a web browser then there should be a "download" button where you can download it to the desktop. After on the desktop you should be able to double click to open it. By using the download command, you may be downloading it into the Downloads folder. So be sure to check there as well. Beyond that, I would need more information as to what the issue could be.
This image is a theme.plist hack