/usr/share/av-userside-plugin.sh

Log into SSH or open "Terminal" in WHM as the 'root' user and run: 

/usr/share/av-userside-plugin.sh

It should look something like this:

[root@server ~]cPs# /usr/share/av-userside-plugin.sh
info [install_plugin] Installing to jupiter
info [install_plugin] Installing imunify-antivirus in Feature Manager ...
info [install_plugin] Done
info [install_plugin] Scheduling task to update sprites
info [install_plugin] Scheduling task to update API spec files
Plugin installed ok
info [install_plugin] Installing to paper_lantern
info [install_plugin] Scheduling task to update sprites
info [install_plugin] Scheduling task to update API spec files
Plugin installed ok

Verify that the "ImunifyAV plugin" option shows in the features list or that the "ImunifyAV" icon shows in each cPanel account.

ImunifyAV – an intelligent antivirus and security monitoring tool for websites with one-click automatic malware cleanup, domain reputation monitoring, and blacklist status check. With ImunifyAV you can: Give your customers complete, automated security to combat viruses, adware, spyware, trojans, and worms.