You can open, preview and annotate your attached PDF files, from within your EndNote library.

Viewing options
Using the Layout options, you can choose to view your PDFs at the right or at the bottom of the screen, or not at all. You can also open a large "reference window" to more easily read and annotate a PDF.

Email a pdf
When the PDF is displayed in the Reference Panel or in a Reference Window, you can email the reference and PDF directly from your Endnote Library, using the Email Reference button.

To view and annotate a PDF
Select a reference from your Endnote library which has an attached PDF. Click the PDF tab in the Reference Panel. (EndNote automatically displays the first PDF file attached to the reference.)

A toolbar will appear above the Reference Panel, with the following options:

• Open PDF
• Save PDF
• Print
• Previous Page \ Next Page
• Go to (page)
• Zoom Out \ Zoom In
• Rotate Counterclockwise \ Rotate Clockwise
• Sticky Note
• Highlight Text
• Find (search PDF)

To add notes to a PDF

1. Select the orange Sticky Note icon from the floating toolbar
2. Navigate to the section where you want to add the sticky note.
3. Click the left mouse button to display a Sticky Note icon along with a Sticky Note text box.
4. Enter your comments in the Sticky Note text box.
5. Click the Save icon in the floating toolbar.
6. Click Yes when prompted.

You can also save your changes by closing the PDF or by navigating away from the PDF (for example, by opening another PDF). Click Yes when EndNote prompts you to save your changes.

To highlight parts of PDF

1. Select the Highlighting icon from the floating toolbar.
2. Select the text that you want to highlight.
3. Note that the selected text is highlighted in yellow.
4. Click the Save icon in the floating toolbar.
5. Click Yes when prompted.

You can also save your changes by closing the PDF or by navigating away from the PDF (for example, by opening another PDF). Click Yes when EndNote prompts you to save your changes.

To hide highlighting and sticky notes
To hide sticky notes and highlighted text, move your cursor over the text. Right-click to display the contextual menu. Select the Hide Notes/Markup option from the menu.

To re-display sticky notes and highlighted text, Right-click again, and then select the Show Notes/Markup.

To delete highlighting and sticky notes
To delete a sticky note, right-click on the sticky note to display the menu, and choose "Delete Annotation". Delete highlighting in the same way.

To search your sticky notes
When searching your Endnote Library, sticky note comments are searchable using the "Any Field and PDF" and "PDF Notes" options from the Field list.

The above information is from EndNote Help Guide.