Installing APKs of unknown sources can be a convenient way to use apps that are not on the Google Play Store, but it also exposes some security risks. Before proceeding, make sure that you only install APKs from reputable sources, and at all times be cautious when installing apps from unknown sources.
To install APKs of unknown sources on Android, follow these steps:
Go to your phone's Settings app. You can usually find this app on one of your desktops or in a folder of the similar name. Alternatively, swipe down from the top of the screen with two fingers and click on the gear icon.
Scroll down to the Security section and click on it. Depending on your phone model plus Android version, the location of the Security section may vary. On older Android versions, you might need to go to the Application Manager or mega888 Applications section.