EndNote's import options include:
PDF File or Folder
Use to import references from a PDF file that has been downloaded to your hard drive. This option allows you to convert existing collections of PDF files into EndNote records with minimal typing and copying by extracting Digital Object identifiers (DOI) from PDF files. The system matches the content against the existing API services by capturing bibliographic content and creating new EndNote records. See Importing PDF Files to Create New Records for specific instructions.
EndNote Import
Used to import text files that have been downloaded from online databases or exported from EndNote using the EndNote format. See Creating a Tagged "EndNote Import" File for more information.
Refer / BibIX
Used to import text files exported from the Refer or BibIX programs. The EndNote import format is based on the Refer/ BibIX format.
Reference Manager (RIS)
Used to import text files exported from Reference Manager, Reference Update, Reference Web Poster, or any other source that uses the RIS format. See Creating a Library from ProCite or Reference Manager.
ISI-CEUsed to import text files downloaded from Web of Science™ Core Collection and other Clarivate Analytics sources.
Note: See Searching Web of Science for information about directly retrieving Web of Science Core Collection records.
Multi-Filter (Special)
A special option for importing files that include references from multiple sources (see Identifiers.
EndNote Generated XML
Used to import EndNote’s proprietary XML format.
Other Filters
EndNote includes hundreds of import filters configured to import data from a variety of online databases. Most likely, the first time you import a file, you will not see the import filter that you need in this list. Select Other Filters from the Import Options list to find the filter that matches the source of the data you want to import. Import filters that you have recently used or chosen as your favorites will be listed in the Import Options list in the Import dialog.
The table in Summary of Output Formats and Corresponding Import Options provides more information about the download formats that work with these filters. See Choosing the Correct Import Filter for information about how to choose the filters to appear in the Import Options list.
ProCite RIS
Use to import text files that have been exported from ProCite (Windows or Macintosh) in the comma delimited format. You may also open native ProCite files using EndNote's Open command.
Use Connection File
EndNote provides the option of using a connection file as an import filter. This is useful if you need to import the Connect.log file generated by using EndNote’s Online Search command to search an online database. The Connect.log file should include all of the references from your previous session. See The Log File for more information.
Note: See Introduction to Filters for information about creating and modifying import filters. All of the import filters (except Tab Delimited and EndNote Generated XML) can be modified.