The is a lifeline for IT pros and power users who value control over their software assets. While Microsoft has hidden this capability behind the Office Deployment Tool, the process outlined above remains the gold standard for creating a portable, reusable, and internet-free installation package.
For a single-file offline installer (Retail version), Microsoft provides an official disk image (.img) that can be mounted and used without an active internet connection after the initial download. Microsoft Office 2019 Pro Plus Offline Installer Download