For macOS Sonoma
If you’re coming to macOS from Windows, you’re probably used to either downloading apps from the Microsoft Store, or downloading an app package from a website and running its included installer. On macOS, there are several ways apps can be installed and uninstalled, which I will give an overview of in this guide. The good news is that whatever methods the developer has employed, the installation and uninstallation processes should seem very straightforward to you, the user.
Mac App Store
Similar to iOS and iPadOS, developers can choose to distribute their apps in the Mac App Store, which can be accessed either from the Apple menu or Applications folder. Either by searching or browsing, locate the app you want to download in the store and click the price, or if it is free, the “Get” button in the toolbar. After authenticating with your Apple ID or Touch ID, depending on your hardware and settings, the app should be downloaded and installed on your Mac and placed in the Applications folder.
A particularly common way to install apps not distributed in the Mac App Store is to download a disk image file from a website. Open this file (saved to the Downloads folder by default) and it should mount like a volume on your desktop.
In this volume, there should be two files, the app, and something like “Applications” or “drag here to install.” Whatever this file is called, it is simply a shortcut to your Applications folder and is trying to instruct you to place the app there to install it. To do this, focus on the app and choose Edit > Copy, (or press Command-C) then open the Applications folder and choose Edit > Paste (or press Command-V). If you’re not logged in as an administrator, you will be prompted to authenticate before the app can be placed in this location.
Note: While it is technically possible to run apps directly from disk images, they will lack access to the full array of system resources, and thus may not work as expected.
Using the Installer app
Another way apps can be installed is with the built-in Installer app on macOS. Apps that use this method of installation are contained in packages that use either the “.pkg” or “.mpkg” extension.
Simply open this file and follow the onscreen instructions, which typically involve clicking continue through an introduction, read me, and license agreement, clicking the install button, and authenticating with your login password, Touch ID, or a paired Apple Watch. If the installer shows a “Customize” button, you may want to click it to see if other files are included in the package that you can optionally exclude from the installation, so as to avoid installing unnecessary bloatware on your Mac.
In theory, simply moving an app to the trash and emptying the trash should remove it from your Mac. However, as many apps deposit small files in various locations throughout your Mac, you may want to use a dedicated uninstaller to complete this task.
Some apps include their own uninstallers from either the menu bar, settings window, or as a separate utility. Otherwise, you can use something like AppCleaner. This free and accessible app allows you to view third-party apps in a list and offers to delete their associated support files, and can also be configured to trigger any time you move an app to the trash.
Alternatively, you can manually remove support files from the Library folders. While apps place files in various locations inside the Library folders, much of them can be found in the “Application Support” and “Preferences” folders.
To access your user Library folder, in Finder, choose Go > Go to Folder (or press Command-Shift-G) and type or paste “~/library” without the quotes. To access the Library folder at the root of your startup disk, in Finder, choose Go > Go to Folder (or press Command-Shift-G) and type or paste “/library” without the quotes.
Caution: The library folder’s contain essential files needed for macOS to function. Therefore, only delete files if you know what they are and know you don’t need them.
While this at first can sound like a lot of information, once you're used to using third-party apps on your Mac, the processes of installation and uninstallation will likely become natural to you over time. More information is available in your Mac's built-in help, Apple Support, and the AppleVis forum, and if you have any questions or believe any of the information in this guide is inaccurate, sound off in the comments.