You can obtain apps from many different sources on your Samsung Galaxy S6. This includes primarily the Google Play Store. But apps can be downloaded also to your phone via the Amazon App Store or another source. Thus, for example WhatsApp can be downloaded on the official website as “.apk” installation file.
If you have the APK file stored on your Samsung Galaxy S6, then you want to install it of course. But first you have to allow the installation outside of the Google Play store in Android. How it works on the Samsung Galaxy S6 we show you here:
Open from your home screen the menu and then the Android settings. Here you can now select the menu item "Lock screen and security". Scroll in this submenu a little way down until you can see "Unknown sources". You must now press the knob here to allow the installation of an APK file permanently.
If you now tap on the APK file saved on your Samsung Galaxy S6, then the installation wizard automatically starts.
But we recommend you to leave this setting "inactive" after installing an app manually because outside the Google Play store no check of malware takes place. Enable this option only if you wish to install one or more apps manually on your Samsung Galaxy S6.