Occasionally, EndNote will not install the Cite-While-You-Write (CWYW) function in MS Word.
Please have a look at these support articles from Clarivate. If the function is still not working, please contact Clarivate support.
Windows: https://support.clarivate.com/Endnote/s/article/EndNote-Windows-CWYW-tools-are-disabled-and-missing-in-Word?language=en_US windows
Mac: https://support.clarivate.com/Endnote/s/article/EndNote-X8-Mac-and-EndNote-online-Mac-CWYW-tools-in-Microsoft-Word-2016-Troubleshooting-guide?language=en_US
