Google introduced the BottomNavigationView in Android Support Library 25.
Steps to create Bottom Navigation View (Imp: Use latest available version of Xamarin Forms)
1. Add A new Page and changed that into TabbedPage as shown in image.
2. Add following line to your TabbedPage tag xmlns:android=”clr-namespace:Xamarin.Forms.PlateformConfiguration.AndroidSpecific;assembly=Xamarin.Forms.Core” and android:TabbedPage.ToolbarPlacement=”Bottom”
3. You can also specify the BarItemColor and Background color of TabbedPage as shown in the below image.
4. Now you can add TabbedPage Children page or create ContentPage inside Tab and you can set Icon and Title of TabbedPages.
Preview: 