Microsoft Word
Once you download and install Mendeley Reference Manager to a computer, you can install the Microsoft Word Plugin. Open the Manager, then click on Tools > Install Mendeley Cite for Microsoft Word. You may have to close and reopen Word for the install to be completed.
Microsoft Word Online
Once you download and install Mendeley Reference Manager to a computer, you can install the Microsoft Word Add-in. Open a new document in Word Online. Click on File > Get Add-ins > My Add-ins > Mendeley Cite. You may have to search the Add-ins for Mendeley Cite.