If you have a pre-existing volume license, you cannot get a "free" ISO, but you can obtain the official installation files: Microsoft 365 Admin Center (Formerly VLSC):
Downloading Microsoft Office 2013 Professional Plus Volume License ISO If you have a pre-existing volume license, you
a sought-after, albeit legacy, treasure. It represents the pinnacle of the "perpetual license" era—no subscriptions, no forced cloud connectivity, just powerful tools that work offline. you cannot get a "free" ISO