Hi @ Thomas Stoker ,
Thank you for posting in this community.
In SharePoint 2019, if you want to be able to open files in web pages, then you need to install Office Online Server. Office Online Server is an Office server product that provides browser-based file viewing and editing services for Office files.
You can follow the articles below to install Office Online Server and configure it for SharePoint 2019:
Please note that Office Online Server is not compatible with some services (e.g. SharePoint) and cannot be installed on the same computer.
- Deploy Office Online Server - Office Online Server | Microsoft Learn.
- Configure Office Online Server for SharePoint Server 2016 - Office Online Server | Microsoft Learn(The article uses SharePoint 2016 as an example, but it also applies to SharePoint 2019).
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