You can upload this set of APKs (and OBBs, if enabled) to the Google Play, or other, store instead of a FAT APK in which all of the selected architectures are included into a single APK. The Split APKs by target architecture option produces one set of APKs and OBBs for each device architecture selected in the Target Architecture list in the Player settings. To optimize for download and installation size, enable the Split APKs by target architecture option in the Player settings.
For more information on OBB files, see OBB Support. The output package includes an APK, and an APK expansion file (OBB) if the Split Application Binary option is selected in the Player settings.
For more information on Player settings, see Player settings for the Android platform. There are two locations to configure settings that affect how your app is built: