// The path to the documents directory.
string dataDir = RunExamples.GetDataDir_LoadingAndSaving();

// Create an object of the Document class
Document doc = new Document();
// Initialize Page class object
Aspose.Note.Page page = new Aspose.Note.Page(doc);
// Initialize Title class object
Title title = new Title(doc);
// Initialize TextStyle class object and set formatting properties
ParagraphStyle defaultTextStyle = new ParagraphStyle
{
    FontColor = Color.Black,
    FontName = "Arial",
    FontSize = 10
};

RichText titleText = new RichText(doc)
{
    Text = "Title!",
    ParagraphStyle = defaultTextStyle
};
Outline outline = new Outline(doc)
{
    VerticalOffset = 100,
    HorizontalOffset = 100
};
OutlineElement outlineElem = new OutlineElement(doc);
// RunIndex = 5 means the style will be applied only to 0-4 characters. ("Hello")
TextStyle textStyleForHelloWord = new TextStyle
{
    FontColor = Color.Red,
    FontName = "Arial",
    FontSize = 10,
    RunIndex = 5,
};
// RunIndex = 13 means the style will be applied only to 5-12 characters. (" OneNote")
TextStyle textStyleForOneNoteWord = new TextStyle
{
    FontColor = Color.Green,
    FontName = "Calibri",
    FontSize = 10,
    IsItalic = true,
    RunIndex = 13,
};
// RunIndex = 18 means the style will be applied only to 13-17 characters. (" text").
// Other characters ("!") will have the default style.
TextStyle textStyleForTextWord = new TextStyle
{
    FontColor = Color.Blue,
    FontName = "Arial",
    FontSize = 15,
    IsBold = true,
    IsItalic = true,
    RunIndex = 18,
};
RichText text = new RichText(doc)
{
    Text = "Hello OneNote text!",
    ParagraphStyle = defaultTextStyle,
    Styles = { textStyleForHelloWord, textStyleForOneNoteWord, textStyleForTextWord }
};

title.TitleText = titleText;
// Set page title
page.Title = title;
// Add RichText node
outlineElem.AppendChildLast(text);
// Add OutlineElement node
outline.AppendChildLast(outlineElem);
// Add Outline node
page.AppendChildLast(outline);
// Add Page node
doc.AppendChildLast(page);

dataDir = dataDir + "CreateDocWithFormattedRichText_out.one";
// Save OneNote document
doc.Save(dataDir);