Wi-Fi Sharing is a nice feature you can find in Mobile Hotspot settings on Samsung Galaxy devices
As we wrote in one of our previous articles, mobile hotspot makes your Android phone work as a wireless router. In this mode mobile data interface works as WAN and Wi-Fi as LAN respectively. But Samsung added a nice expansion feature to Mobile Hotspot mode in their flagship Galaxy devices – it is called Wi-Fi sharing. It works as follows. In the case if one of the wireless networks (which your phone was previously connected to) is detected, your S9/S9+ will propose to redistribute its Internet connection instead of wasting its cellular data. In such a way your Galaxy phone can connect to your home wireless network and connect up to ten devices via its own hotspot.