As mentioned in the CA Overview for a CA to be trusted by an organization it has to be added to the trusted root store of all their devices. This guide will guide you on how to install it in the most common Root Stores.
Usually MDM solutions is the preferred way IT Admins install internal Root CAs as a trusted authority in all of the corporate devices. To do this in Microsoft Intune, follow this guide
In Windows, Root CAs can be added in two different stores: The User store (Only for the current user), The Local Store (For all users, Require Administrator Permissions)