When it comes to installing applications from outside the Play Store, Chromebooks are at a disadvantage. On normal Android devices, all it takes is enabling ‘Apps from Unknown Sources’ in the settings (or doing it on a per-app basis on Oreo). Unfortunately, sideloading APKs on Chromebooks requires enabling Developer Mode, which disables boot verification and other security features. It also requires users to press a key combination when you boot up (on most models) – Google really doesn’t want you enabling it.
Chrome OS may soon allow sideloading Android apps without Developer Mode was written by the awesome team at Android Police.