If you have an enterprise account with Adobe, you probably don't have Adobe Creative cloud to install Add-on's.
Check out these instructions from Adobe:
The commands to use the Extension Manager in a serialized/deployment environment:
For deployment - this requires a Extension Manager Command Line - for more information click here.
Using standardized deployment tools*, copy the contents of the EM command line to a predetermined location on the user’s desktop (e.g. ~/Desktop/ExMan on Windows or /usr/local/ExMan on Mac). This step is only required if the client machine does not already have EM CMD line installed.
Using standardized deployment tools*, copy the extension ZXP files to a predetermined location on the user’s desktop (e.g. ~/Desktop/extensions on Windows or /usr/local/extensions on Mac)
Package Adobe CC products using CCP [nothing new here]
Deploy Adobe CC products using standardized deployment tools* [nothing new here]
After the CC products are installed, use the standardized deployment tools to run Extension Manager Command Line foreach ZXP in the directory containing them.
1. In Mac OS: ./Contents/MacOS/ExManCmd – -install myaddon.zxp
2. In Windows: ExManCmd.exe /install myaddon.zxp
Optional: verify the installation of extensions
1. In Mac OS: ./Contents/MacOS/ExManCmd – -list all
2. In Windows: ExManCmd.exe /list all
If this doesn't work please email Enterprise-Support@adobe.com.