setup.exe /configure configuration.xml That’s it. Office 2019 will install without downloading a single byte from the internet. You will find websites offering a 3.5GB "Office 2019.iso" file ready to go. Do not download those.

A: No. This is strictly for perpetual Office 2019 licenses. M365 requires the subscription installer.

Next time you reformat your hard drive or buy a new laptop, you won't be stuck waiting for a 4GB download. You’ll just plug in your USB drive and be working in 5 minutes.