What version of Office 2019 works with High Sierra 10.13.6

Office is now known as (part of) Microsoft 365, and you might be able to run that hosted here.

For info on older Microsoft Office (perpetual packages) for Mac versions, best check with Microsoft.

Here is a starting point:

… https://learn.microsoft.com/en-us/officeupdates/update-history-office-for-mac

Office 2019 follows the usual Microsoft policy: “Office for Mac is supported on the three most recent versions of macOS. As new major versions of macOS are made generally available, Microsoft will stop support for the oldest version and support the newest and previous two versions of macOS. Product functionality and feature availability may vary on older systems. For the best experience, use the latest version of any operating system specified above.”

Per this: https://answers.microsoft.com/en-us/msoffice/forum/all/does-office-2019-run-inn-high-sierra/5b79e910-5b9f-427d-ad48-0ed56833b887 you need 16.43 or earlier. (There seems to be a download of that available at that link, too.)

If that does not work, you’ll have to discuss Microsoft licensing and limits and refunds with Microsoft.

LibreOffice is a free alternative, though the current version of LibreOffice also won’t run as far back as macOS 10.13. You’ll need LibreOffice 4.3 or earlier and an equivalently old Java, per:

https://www.libreoffice.org/get-help/system-requirements/#Apple

Apple iWork Pages is another potential option, but new downloads aren’t available as far back as macOS 10.13. If you already have iWork “purchased” (it’s free), then you can re-download that from the previous purchases in the app store, and iWork can read and write many Office files.

Windows is usually a better choice for sites wanting or needing Office, and for sites needing or wanting to run older apps and tools for longer, too. Windows and Azure are obviously the focus for Microsoft.

MrHoffman wrote:

LibreOffice is a free alternative, though the current version of LibreOffice also won’t run as far back as macOS 10.13. You’ll need LibreOffice 4.3 or earlier and an equivalently old Java, per:

https://www.libreoffice.org/get-help/system-requirements/#Apple

LibreOffice 7.4.7 ran on High Sierra when it first came out. Later, after 7.4.7 was no longer one of the two most prominently featured versions, the release notes changed to say that the requirement was Mojave.

I'd still take that as a starting point for poking around in the archives. E.g., is there a 7.4.7.0, or a 7.4.6, build that will run on High Sierra? The article to which you linked, that mentions LibreOffice 4.3, also talked about running that version of LibreOffice on versions of Mac OS X as old as 10.6 (Snow Leopard).

No version of Microsoft Office now works with macOS High Sierra unless it was already installed, licensed, and backed up on Time Machine. If on Time Machine, it can be restored to the same Mac and hard drive from which it was originally installed and licensed. Microsoft only supports Microsoft 365/Office 2021 for Mac installations in Monterey, Ventura, and Sonoma. Office 2019 for Mac was retired on Oct 10, 2023.

You might be able to use the free Microsoft 365 Online which is all in Microsoft's OneDrive and requires you to be signed into a Microsoft account for its use. If not…

That leaves an older version of LibreOffice Suite and the last version that supported High Sierra is 7.4.7.2 whose last version for High Sierra installer is available for download as LibreOffice_7.4.7.2_MacOS_x86-64.dmg. Unless you plan to do anything with the LibreOffice database (Base), then you do not need to install Java, and at that vintage, it was likely Java 6 and may not work with the current Java. One can disable LibreOffice from needing Java in its Preferences : Advanced panel and unchecking Use a Java runtime environment. It simply is unnecessary for normal LibreOffice usage.