This example shows how to use the ITextDocument.SetText method to programmatically add text to a RichEditBox. <RichEditBox x:Name="richEditBox" Width="500" Header="Notes"/> richEditBox.Document.SetText(Windows.UI.Text.TextSetOptions.None, "This is some sample text"); This example shows how to edit, load, and save a Rich Text Format (.rtf) file in a RichEditBox. <RelativePanel Margin="20" Horizonta