.APK File Extension
Full form: Android Package Kit
What is a .apk file?
The package format used to distribute and install apps on Android phones. Files that end with .apk belong to the system family of file types, so your computer links them with a suitable program automatically.
Where is .apk used?
Installing Android apps outside or inside the Play Store. Because the format is so common, almost every modern device and software understands it.
Examples of .apk file names
myapp.apk
How to open a .apk file
You can open it with: Android phones, Android Studio. If it does not open, check that the file is not damaged and that you have downloaded it fully; also confirm that the extension was not renamed by mistake.
Quick tips
Never rename a file just to change its extension, because that does not convert the data inside. Use a proper converter or the Save As / Export option. Keep a backup copy of important system files before editing them.