For EndNote X9 and Word on Macintosh:
The simplest way to get the tools to appear is to open EndNote, and go to the EndNote menu. Select "Customizer" from the EndNote menu. Check the box in front of the "Cite While You Write" option. Click next until the Customizer is finished. Open your EndNote Llibrary then open Word and check the Tools menu for the EndNote submenu.
If you're not running Word 2011 or 2016, or these instructions don't work for you, please search the EndNote FAQ for instructions on your version of word and for alternative methods.
Mac Sierra, High Sierra, and Mojave Users
MacOS versions 10.12 (Sierra), 10.13 (High Sierra), and 10.14 (Mojave) contain features to save the contents of the Documents folder in iCloud and to "optimize" storage by storing less-used files only in iCloud online. EndNote libraries stored in iCloud, even when stored on both the hard drive and online, are subject to corruption over time. If you choose to store your documents in iCloud, we suggest creating a separate folder in your home folder and saving your EndNote libraries there. Do not store EndNote libraries in iCloud or any other cloud-syncing folder, and do not store EndNote libraries in the Documents folder if you have selected the option to store documents in iCloud.
Tips for success:
Safari and EndNote
We recommend you use Mozilla Firefox or Google Chrome as your browser when searching databases to export references to your EndNote Library. The Safari browser will always send the reference to the downloads folder first which means an extra step for you to put it in your EndNote LIbrary.