My Android phone is not installing apk files anymore, how to fix it?

Another typical cause of the App not installed error is insufficient free memory on your device's internal storage. The majority of users believe that the apk file size represents the app's actual size. This, however, is not the case. The apk file is actually a bundled version of the application. The package installer expands the apk file and copies the additional files to your device when you install the program.

• The remedy is self-evident: you must clear up RAM on your smartphone.
• Remove certain applications that you don't use too often to do this. Go to Apps & Notifications>Apps>Settings>Tap the app you wish to uninstall>Click Uninstall.
• Transfer huge files from your device's storage to an SD card or another storage medium.
• Clear the app cache from your phone's Phone Manager as well. Install a Phone Manager from the Play Store if your smartphone doesn't come with one.
• Install the app again once you've freed up enough storage space on your device. It should go through the installation process without any issues.