The same margin on all four sides

<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  Title="About WPF" 
  Background="Red">

    <Canvas>


  <Border BorderBrush="Black" BorderThickness="1">

    <Label Margin="12" Background="Aqua">12</Label>
  </Border>
    </Canvas>

</Window>

