In recent years, Apple has made it increasingly difficult for users to install apps from sources other than the App Store on their iOS devices. However, there are rumors that Apple may eventually opens their systems to sideloading apps with the next release of iOS 17.
Something that's been possible for over a decade, using AppDB with signing certificates or a "jailbreak".
Installing programs on your smartphone from locations other than the official App Store is known as sideloading. This can involve downloading apps directly from websites, installing them through developer accounts, or installing them from third-party app stores.