For apps that are not installed via an App Store… most will come in either an installer as a PKG file or as just the app files inside of a ZIP or DMG container.

For apps that are not installed via an App Store… most will come in either an installer as a PKG file or as just the app files inside of a ZIP or DMG container. With PKGs you double click the file and it leads you through the installation process. With DMG, these mount as disk images and you can then just drag the app into the applications folder. Sometimes they include a link inside the DMG to that applications folder to simplify that process. With ZIP, you double-click the zip file and it unpacks in the current directory. Then you drag the app into the applications folder. These are mainly uses by individual developers or small shops who don’t want to go to the trouble of a PKG or DMG container. Uninstall generally just means dragging an app from applications to the trash can. There is no registry and most apps don’t install helper apps. Those you usually uninstalled via the PKG.