What are third-party apps (custom apps)?

Third-party apps (sometimes referred to as “custom apps”) for macOS are apps that aren’t available from the Mac App Store and must be downloaded from developers’ websites. Anyone who has browsed Apple Business Manager for apps has likely noticed the shortage of popular programs like Zoom or Google Chrome. These are among the many popular apps that are not currently listed in the Mac App Store and must be accessed through a developer’s website.