Attaching files, such as PDFs, Word documents, PowerPoint or Excel files keeps the full text of your references, and any supporting files easily accessible within your EndNote library. (See Finding Full Text to learn how to search for the full text PDFs of an article.)
DO NOT attach figures, charts or graphs that you want to cite using the file attachment feature. (See Create and Edit Reference for more information.)
There are multiple ways to attach PDFs and other files to the corresponding EndNote reference. You can also attach multiple files to a reference.
Select the file you want to attach from your computer and click Open to attach the file to the reference
When attaching PDFs the name of the PDF will automatically be changed to a combination of the author and the title of the reference. You can change the attached filed naming convention from the navigation drop-down menu under Edit > Preferences > PDF Handling
EndNote can also import a PDF or a folder of PDFs into your library and automatically attach them to the corresponding reference provided the reference and the PDFs have DOIs.
in your EndNote library use File > Import > Folder. Select "File" if you are only importing a single PDF or Folder if you are importing multiple PDFs stored in a folder.
Use the Browse button to navigate to the file or folder where the PDFs reside, select any additional options you wish and click "Import" to import the PDFs.
Provided the references in your EndNote library and the PDF both contain the DOI EndNote will automatically match and attach the PDF to its corresponding reference in your library.
You can open, view, annotate and perform other functions to PDFs attached to references by clicking the PDF tab.