For runtime, you basically need a bunch of files (QuickOPC .NET assemblies), and register one of them properly (see the doc); plus, the QuickOPC license needs to be present on the system where Excel runs.
For development (if we define development as creating Excel worksheets with live OPC data), actually the bare necessity is the same as for the runtime (above), because the live cells contain Excel's RTD function which can be created by hand (also described in the doc). But, to make this process easy, by drag&drop or copy/paste, Connectivity Explorer can (and is) normally used to format the formulas with RTD functions.
From: OPC Labs Contact Form - T.
Sent: Monday, December 10, 2018 10:15 AM
Subject: OPC Labs Contact Form - Excel Option for QuickOPC
Regarding OPC UA client plug in Excel Option for QuickOPC
The plan is to install software on a laptop during commissioning. Then, as a permanent solution, install software on a workstation / server. When the permanent solution is in place, software on the laptop will be uninstalled.