It’s easy to wind up with multiple Apple IDs that you accrue over time, including for long-time Mac users who originally had a cloud-based account and an iTunes Music Store account, both of which migrated into separate Apple IDs. This can be particularly hard to manage with media and purchases, the collective category Apple uses for all the stuff you might buy from them.
In macOS 10.14 Mojave and earlier, there wasn’t as much transparency about which accounts were used for which purpose. You needed to launch every app with an account associated, like the App Store and iTunes, and check account settings. In some cases, you need to dig into account settings to check on subscriptions, too.
