The Client Integration Plug-in provides access to a virtual machine’s console in the vSphere Client and provides access to other vSphere infrastructure features. The Client Integration Plug-in also let you deploy Virtual Appliances and log in to the vSphere Client using Windows session credentials.
If you are using vCenter Server 6.5 or 6.7, you do not need to install the Client Integration Plug-In. For more information, see VMware KB Article 2145066 for more details.
If your are using vCenter Server 5.5 or 6.0, see Installing the Client Integration Plug-in for vCenter Server 5.5 and 6.0.