If you're looking to access applications outside of the Apple App Store, you'll need to make some changes to your Mac's security and privacy settings. To do this, open the System Preferences window and select Security & Privacy. On the General tab, click the lock in the lower left corner and enter your computer username and password to unlock the settings. If you see a warning message, it means that the application isn't notarized and Apple couldn't scan it for known malicious software. This is different from iPhones, where the only way to get apps is through the App Store.
If your Mac is configured to support apps from the App Store and you've identified developers, you'll be asked if you're sure you want to open a new app for the first time. Developers often use TestFlight to distribute apps that aren't fully approved for the App Store either. Under legislation recently introduced by the EU, Apple would be forced to allow users to install apps from outside the App Store. In addition to allowing third-party stores on its platform, Apple would also have to let users install applications from third-party sources (a process known as sideloading) and let developers use the App Store without using Apple's payment systems. If the new Digital Markets Act (DMA) becomes law in Europe, Apple will be required to give its iPhone and iPad users access to third-party app stores and apps not found in its own app store.
By default, your Mac's security and privacy preferences are set up to allow apps from the App Store and identified developers. To protect Mac users from malware, Apple has a feature called Gatekeeper that blocks some third-party applications downloaded from the Internet. So, if you can't find an app in the App Store, you'll need to download it from the developer's website. Google already offers similar options on Android devices, which must be manually deactivated in order to download applications from third-party sources. Although Macs have long allowed users to download applications from outside of the official Apple store, Apple has argued that this approach is not appropriate on iPhones because these devices contain more sensitive information.
