A File attachment annotation embeds a file at a selected location in your document, so that after the exportation as PDF, the reader can open it for viewing. By attaching files as a comment, you can reference longer documents that cannot easily be pasted into a sticky note or text box. To view an attachment, the reader must have an application installed that can open the attachment.
To add a File Attachment:
In the Annotation pane:
Select File attachment in the drop-down list of Annotation types
Click on the page where you want
the icon of an attached file to be displayed. The icon shows a paper
clip 
The file browser window opens. Select the file to attach.
The annotation is created. The name of the file attachment is displayed above the color palette.
You can move the position of the
icon when it is selected and the move
cursor appears 
Edition options:
Icon Color: quick color selection or advanced color selection
Add a Comment: in some PDF viewers, this comment is shown when the mouse cursor runs over the icon.
For more general information on annotation mode, see chapter Using_Annotations.