xamarin forms android without header code example
Example: xamarin remove title bar
NavigationPage.HasNavigationBar="False"
//ex MainPage.xaml
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:local="clr-namespace:APPNAME" x:Class="APPNAME.MainPage" BackgroundColor="#edfffb" NavigationPage.HasNavigationBar="False">