LoginPage.xaml

<?xml version="1.0" encoding="UTF-8"?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" x:Class="MyCoolApp.LoginPage">
  <ContentPage.Content>
      <StackLayout>
        <Entry x:Name="usernameEntry" Placeholder="Username" />
        <Entry x:Name="passwordEntry" Placeholder="Password" IsPassword="true" />
        <Button x:Name="loginButton" Text="Login" Command="{Binding LoginCommand}" />
      </StackLayout>
  </ContentPage.Content>
</ContentPage>