//Create a pdf document
PdfDocument doc = new PdfDocument();
//Add page
doc.getPages().add();
//Set tab order
doc.getPages().get(0).setTabOrder(TabOrder.Structure);
//Create PdfTaggedContent
PdfTaggedContent taggedContent = new PdfTaggedContent(doc);
taggedContent.setLanguage("en-US");
taggedContent.setTitle("test");
//Set font
PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Times New Roman",Font.PLAIN,12), true);
PdfSolidBrush brush = new PdfSolidBrush(new PdfRGBColor(Color.black));
//Append elements
PdfStructureElement article = taggedContent.getStructureTreeRoot().appendChildElement(PdfStandardStructTypes.Document);
PdfStructureElement paragraph1 = article.appendChildElement(PdfStandardStructTypes.Paragraph);
PdfStructureElement span1 = paragraph1.appendChildElement(PdfStandardStructTypes.Span);
span1.beginMarkedContent(doc.getPages().get(0));
PdfStringFormat format = new PdfStringFormat(PdfTextAlignment.Justify);
doc.getPages().get(0).getCanvas().drawString("Spire.PDF for .NET is a professional PDF API applied to creating, writing, editing, handling and reading PDF files.",
font, brush, new Rectangle(40, 0, 480, 80), format);
span1.endMarkedContent(doc.getPages().get(0));
PdfStructureElement paragraph2 = article.appendChildElement(PdfStandardStructTypes.Paragraph);
paragraph2.beginMarkedContent(doc.getPages().get(0));
doc.getPages().get(0).getCanvas().drawString("Spire.PDF for .NET can be applied to easily convert Text, Image, SVG, HTML to PDF and convert PDF to Excel with C#/VB.NET in high quality.",
font, brush, new Rectangle(40, 80, 480, 60), format);
paragraph2.endMarkedContent(doc.getPages().get(0));
PdfStructureElement figure1 = article.appendChildElement(PdfStandardStructTypes.Figure);
//Set Alternate text
figure1.setAlt("replacement text1");
figure1.beginMarkedContent(doc.getPages().get(0), null);
PdfImage image = PdfImage.fromFile("E-logo.png");
Dimension2D dimension2D = new Dimension();
dimension2D.setSize( 100,100);
doc.getPages().get(0).getCanvas().drawImage(image, new Point2D.Float(40, 200),dimension2D);
figure1.endMarkedContent(doc.getPages().get(0));
PdfStructureElement figure2 = article.appendChildElement(PdfStandardStructTypes.Figure);
//Set Alternate text
figure2.setAlt( "replacement text2");
figure2.beginMarkedContent(doc.getPages().get(0), null);
doc.getPages().get(0).getCanvas().drawRectangle(PdfPens.getBlack(), new Rectangle(300, 200, 100, 100));
figure2.endMarkedContent(doc.getPages().get(0));

//Save to file
String result = "CreateTaggedFile_result.pdf";
doc.saveToFile(result);
doc.close();