APK is similar to other software packages such as apps in Microsoft Windows, this format used by the Android operating system.
How to install APK file?
By default, Android device allow to install apps only from Google Play. To install software from other sources, you have to enable installation from third-party sources.
on Android 8+:
From a Home screen, swipe up or down from the center of the display to access the apps screen
Navigate: Settings Settings icon > Apps
Tap Menu icon (upper-right)
Tap Special access
Tap Install unknown apps
Select the unknown app then tap the Allow from this source switch to turn on Switch on or off Switch off
On Android 7 and lower:
From a Home screen, navigate to Settings
Tap Lock screen and security
Note If unavailable, tap Security
Tap the Unknown sources switch to turn on or off
Note If unavailable, Unknown sources to turn on or off. Enabled when check mark is present
To continue, review prompt then tap OK.
What is APKS file?
APKS file is Android App Bundle. Installation APKs file is also more complicated than Installation APK. You need to use a 3rd party application like SAI (Split APKs Installer), which is the simple APKs file installation and export tool.
How to install APKS file?
To install APKs, you need a tool called Split APKs Installer (SAI). You can refer here. It is simple to use it
Wait for the installation process to complete
What is OBB file?
OBB file(s) is APK Expansion Files used by some Android apps, because APK can save only 100 MB of data, the excess information is stored in the OBB files.